As a chemist, here are a few thoughts: 1) Of course it is a bleaching process. 2) Sunbrithing probably works because the Chromophores are more susceptible to Photooxidation than the bulk plastic. 3) Hydration (Addition of Hydrogen) with H2O2 sounds like BS to me. 4) The electrolysis isn't likely to work in it's current form, because elemental Oxygen and Hydrogen aren't very reactive at Room Temperature (RT). The most likely bet is if the plastic part itself acts a an electrode (hard to implement due to conductivity) 5) As you said, the corrosion of the Anode is a well known problem in Electrolysis. The safest way to prevent this is to use Nobel Metals like Gold or Platinum at the Anode. Silver, Titanium, Lead or Carbon may also work. Lead (IV) oxide is often used for this in industry. Corrosion at the Anode is very dependent on the pH of the Electrolyte and Current density. The blackening of the Cathode is likely due to dissolved Anode matter being reduced at the Cathode. 6) Using Sodium Chloride as an Electrolyte is a bit dangerous, as it can lead to chlorine formation. This might work to bleach the plastics at the Anode though. 7) Hydrating the Plastic with Hydrogen is unlikely to succeed, this reaction is usually done in solution with Palladium on Carbon as a Catalyst. 8) The most amateur accessible method to hydrate the plastic surface could be using tin in hydrochloric acid. This will form SnH4 which might react with the Chromophores. Other reagents could be Diimide (made from Hydrazine and H2O2) as well as Sodium Borohydride and Lithium Aluminium Hydride. The later two are unlikely to react with the double bonds in the Chromophore (unless these double bonds are Michael acceptors), it could still have an effect on some functional groups that could improve (or worsen) the situation. 9) H2O2 decomposition can be catalyzed by adding Potassium Permanganate or Dichromate in very low concentrations. Copper sulfate could also work. These salts can leave a stain on the plastic though.
Hey Birt! So, I watched the whole thing before commenting. You do keep saying that there is no way to stop the oxidation process. But there is. You touched on it at 34:12, but I felt you should have elaborated on it. People often ask me if there is a way to prevent yellowing and I will say to remove the oxygen. Even covering something in plastic wrap or aluminum foil is helpful as it keeps out fresh oxygen. But a vacuum sealed bag probably works best, or possibly a bag filled with nitrogen, CO2, or some other inert gas. On interesting anecdote is that I have an Atari ST that has yellowed significantly around the power supply from heat. But there was a paper sticker on the plastic in that spot. Removing the sticker revealed no yellowing underneath. Since heat was the catalyst here (not light), clearly the sticker didn't prevent that area from becoming hot. So the only conclusion is it stopped fresh oxygen from contacting the plastic. I would also comment about Sodium Percarbonate. It does work very well for retr0brite. But, as you mentioned, it is very alkaline. I destroyed a Macintosh LC top cover using this stuff because it ate away the RF shield, which unfortunately cannot be removed from the plastic. But the plastic itself came out looking great. So as long as there are no metal parts, the Sodium Percabonate may even be a better choice as it is easier to store, I think.
Hi David, thanks for your thoughts. On the subject of preventing re-yellowing the paper that Perfractic found a few years ago outlined some very interesting experiments. After weathering the samples they were wrapped in aluminum foil and kept at -10C and they still yellowed. However, they whitened up again just being out in the normal daylight through a window. This correlates with anecdotal evidence reported by some in the vintage computer community that even when wrapped up and in the dark some items yellowed a bit. The last video GadgetUK did he noted this with his A1200 which had been sitting in the corner of a room for a few years out of direct light, it had darkened up a bit but after a few hours in the garden and a few days of using it whitened up again. The oxidation problem can be reduced by all the methods you describe but there is still this other phenomenon that can happen and it does not seem to be preventable. From what I can tell it has something to do with certain molecules coming into equilibrium in different configurations when in the light vs. when in the dark.
It doesn't make sense to me that you can fix a problem caused by oxidation with oxidation, unless it has to do with the amount of oxidation. If stored in-doors, and especially in a container, the amount of oxidation is low. If you put it out in the sun, the oxidation is high, and you can reverse the effects of low oxidation to a certain extent. The sticker example is an interesting one, though. What if the explanation to that one isn't the lack of oxygen, but the adhesive and sticker itself? I think heat is a greater contributor to yellowing than light, and maybe the idea about the reason being light was due to the fact that heavily yellowed plastic often has been placed in a window area. Yes, there is more light there, but also more heat, from the sunlight or an actual heater. Window glass, at least nowadays, blocks a lot of UV-light.
Re: Yellowing in light vs. dark, there's definitely evidence of both cases. E.g., I have some large computer cases that obviously yellowed more where exposed to light(?), in that a certain side was lighter or darker than another, and if something (a monitor, e.g.) sat on top of the case, the area directly underneath was less affected. In contrast, Plextor CD drives have a tendency to yellow quite a bit. I had a couple of SCSI drives that I used back before SATA -- maybe had them installed in a case under a desk for a couple years in a room with some ambient light through a window, but nothing direct. I then put them in a shoebox and kept them in storage, partly in a garage that tends to stay cool (50-65F in the winter due to a heater, 55-70F in the summer due to northern climate) for about fifteen years, and they turned _quite_ yellow during that time. My supposition here is a rather pedestrian one: It varies a lot, presumably by the type of plastic, and whatever colorants and treatments they use. I suspect there is more than one mechanism at play, and any blanket statement that "it's light" or "it's heat" or "it's just oxidation" probably applies to one or more, but probably not all of those cases.
Just a side note, I wouldn't try CO2 as a gas for preservation. It's actually acidic. Generally you want to lean toward the basic side of things for preservation. A lot of museums look for acid free, and buffered (doped with a base chemical, like baking soda) materials to help preserve things. This assumes the item itself isn't so acidic that it will be harmed by reacting with a base, of course.
I tried electrolysis of salt water, I had it outside but in a covered area, so chlorine gas would harmlessly dissipate, however NaCl + H20 also produced NaOH (caustic soda) and leaving overnight with 12Volts at 1Amp produced so much NaOH it not only ate the electrode but also the alligator clips connected to them.
Excellent work Jeff! I observed most of the effects you described 1:1 during the course of my own retrobrighting experiments over the years. Turns out I had only very vague ideas about the science behind it though. At least I stopped blaming the Bromine pretty early on after reading up on it. ;) Thanks for this video, hopefully it's going to help clear things up and the future is going to look a bit brighter... ;P
@@HeyBirt - I've been doing retro-brighting for many years by simple trial and error. heh While I just found this video, most of my methods are similar with some differences which might help you, especially the HCl activator method.
Here are some tips for improving retro-brighting making it better and faster. Before you start, it's highly recommended to wash all the parts using a nail brush with soapy detergent like dish-washing liquid and warm water, then rinse it several times with clean water to get rid of any residue, which will help the bleaching process to be more even. Using peroxide cream is relatively weaker than peroxide liquid (also in higher concentration), and tends to leave shadow lines due to uneven coverage. I recommend using a standard Rubbermaid/Hefty or similar plastic storage tray at least 5 inches tall, and long and wide enough to fit your largest parts.
1. Use a 20-30% peroxide liquid available at swimming pool supply stores sold as "Pool oxidizer/disinfector" in one gallon jugs (about $30usd/gallon).
2. As a common bleaching activator, add a quarter cup of TAED (Tetra-Acetyl-Ethylene-Diamine) to each one Liter (quarter gallon) of peroxide. TAED is available online as powder and in some OxiClean formulations (read the fine print), or Clorox2 at supermarkets. Pure TAED works well, but there's even a better one, read on.
3. If TAED is unavailable, add a quarter cup of 30% Hydrochloric acid (HCL is sold at hardware stores as Muriatic acid) to each one Liter (quarter gallon) of peroxide. HCL may be substituted with one cup of vinegar (a weak Acetic acid) or citric acid (even weaker), but HCL works best due to the formation of Peracetic acid, a very strong bleaching agent (HCL is my favorite method).
Feel free to experiment with various activator to peroxide ratios, and see what works best for you. Whenever working with corrosive and oxidizing chemicals, always wear rubber gloves and safety glasses for protection!
Contrary to popular belief, basically it's not the UV or the Sun's light what speeds up the bleaching process, rather it's the heat from those sources. So, you can just leave it outside under the Sun, or put a water heater coil set to low/medium into the peroxide mixture, or place the tray into the oven set to low/medium with the door open (important!) for a couple of hours. If you have a cooking thermometer, try to adjust the peroxide mixture at around 70C degrees or 160F (higher could melt the plastic). Stir the mixture often with a plastic or wooden spoon, and check on the color change.
Once it looks satisfactory, wash all the parts thoroughly using a nail brush with soapy detergent like dish-washing liquid and warm water to get rid of all the chemicals, then rinse it several times with clean water. I've done many retro-brighting jobs, and this method works really well.
P.S. There's still one more thing to try, which is using plain and strong Clorox bleach (Sodium Hypochlorite 10%) for a couple of days, since that's a really good bleeching agent too (we shall see ;).
Great video Jeff! I can tell a huge amount of work went into this. So great that we now have a definitive source of real scientific data on this subject that we can point people toward - whether or not they'll listen is a different matter, of course...
This is the most comprehensive explanation of and investigation into retrobrite that I've seen. TBH I've been reluctant to try retrobriting in the past, but I have a couple of machines where I'm not entirely happy with the patina and I'd prefer to have them look less yellowed. Many thanks for this video.
Excellent video. Super informative. I appreciate all of the research that went into this -- well done. I have had very good success with full immersion Retrobriting using liquid H2O2 and a 1000W UV grow lamp. I also tested Sunbriting -- it has worked well, too. Great work, Jeff. 👍
Holy Cow! AWESOME! Your work has saved me months of research. My pet peeve is when people make claims/assertions without any documentation is a waist of time. Your actual scientific approach: formulate hypothesis, identify possible causes for discrepancies, test - test - and test again, attempt to eliminate possible discrepancies, THEN formulate the outcome. Wow! I just found your channel but I'm a huge fan now. Keep up the good work!
I knew Retr0brite was bleaching. I can also confirm that ABS turns yellow in the dark. Last year I did an Alarm System takeover and the old Alarm System's communicator was in a dark attic. That thing was so yellow, the case was fragile it was like poking your finger through a wet sheet of paper. The previous tech left his name and install date in the panel so it was around 11 years. I believe it got like that from the Humidity and Heat. Also ABS in it's "natural" state as in color is anywhere from a off white to a yellow color depending on the chemical mixture before bleaching, dyes and color additives are added.
I did some research a few years ago about this and found very similar results to yours (but not as thorough) One of the things that should be elaborated on is the mechanism of the yellow/bleaching of these plastics. The initial yellowing isn't just caused by O2 in the air. It's caused by the natural breakdown process of O2 into an oxygen radicals and ozone (O3). The ozone does it's thing, usually just reacting with itself, but the oxygen radical almost immediately reacts with anything it bumps into. Most of the time it reacts with ozone, reforming O2, but this can also be the CH groups in plastics, turning them into ketone groups, which is one of the ways that plastics yellow (cause afterall, there's more conjugated bonds which act as chromophores). Heat and UV, like you said, increase this breakdown which is why it's inevitable. I know it all too well as a woodworker. The same problems happen there However, what I suspect, is that these oxygen radicals also act as a way to remove these ketone groups, forming ozone in the process (which is unstable) among other molecules. This process is generally an oxidizing one chemically speaking. Sun bleaching makes sense with this process. But the issue is that you need to start from the oxidized plastic before hand, otherwise you're doing the yellowing reaction mechanism. Hydrogen peroxide provides radicals that do the same thing as O2's breakdown. I think this is where the misguided suggestion of ozone generators came from. Those generators aren't great at making the radicals themselves. In addition, in my research, I found that someone successfully achieved de-yellowing with other bleaching agents. Chlorine gas is a bleaching agent (but not used as one), and it managed to de-yellow just as well as H2O2. This is despite it not making radicals, but instead it being a very strong oxidizer (the molecule that takes electrons). So a suggestion for future experiments is to try not only other bleaching agents (like household bleach), but even strong oxidizers (within the realm of safety) such as nitric acid and sulfuric acid. It is unlikely that methods using these oxidizers would be any more viable than just H2O2, but it would be more evidence of the true mechanisms of de-yellowing of plastic. Maybe Nile Red or Cody could take a look into something like this
I'm only a few minutes in but I love your explanation of light. It reminds me of how, when learning this in school (about the spectrum) I became hit by a new fact.....I can't see ANYTHING except for light. With the blue truck example you gave, I can't see a truck at all. I can only see light bouncing off an unseen object. The example my teacher gave was a chair and I recall being awestruck at the epiphany that I can't see a chair at all, only light bouncing off the chair. It's both obvious and amazing at the same time.
I had a similar epiphany when I was a teenager when I finally understood capacitive and inductive reactance. It was like a curtain had been pulled up and I saw the obvious for the first time.
You can straight up destroy fabric with nothing but a bleaching agent. It weakens the fibers of the cloth and if you soak those socks long enough in a concentrated solution they'll just fall apart. No idea if it has a similar effect on plastic but it would be greatly reduced anyway considering the thickness of the substrate.
I can soak a piece of metal in a weak caustic solution and get it very clean. If I use a strong solution I can dissolve the part. Saying the former is a safe process does not imply the later is.
You say that the plastics you are trying to get back to original are ones that have been stored in the dark. I have been retrobriting my lego as they parts that have changed colour are ones that have been exposed to sunlight as by being near a window. Some sets I have bought have been burned on one side where they faced or were in a windowsill and the side facing the inside of the room were their original colours. So I have been using a 3% solution, warm water and outside on a hot day, and the container sealed with cling film to create a hothouse and have been having good results. On a really bright day the greys, whites and yellows can be bought back within a day. At max I would leave in for 36hours. After that there is some colour degradation.
"You say that the plastics you are trying to get back to original are ones that have been stored in the dark." No, I did not say that. I said that some plastics which have already yellowed may continue to yellow in the dark, even after they have been Retr0Brited. This phenomenon is described in a paper included in the link in the description.
Historically Potassium Permanganate as a catalyst has been used to accelerate the decomposition of Hydrogen Peroxide. Perhaps a small amount would help with the liquid immersion method. A large amount would probably be counter productive as it would colour the liquid and might affect the plastic being retrobrighted.
Thanks. I have a suspicion there might be some relationship between H2O2 concentration and temperature, i.e. at lower temperatures a 6% concentration of H2O2 is not as 2x as effective as 3% as the temperature of the plastic limits the reaction. Perhaps though a 3% concentration of H2O2 with a catalyst would be as effective as 6% would be if both were at 50C. I don't have the equipment to make that detailed of a study though.
24:30 mark: "..try again if the electrode corrosion issue can be solved." Before Energizer/ Duracell alkaline batteries were in all the stores, they were carbon-Zinc construction, like the Ray-O-Vac "Heavy Duty" with a carbon rod electrode. The biggest of those rods I got came out of the No. 1209 "Lantern" flashlight 6Volt block. Those blocks seem to mostly be inside older camping gear in stores that sell donated items.
Carbon or graphite rods would have worked better. I'm not sure that I'll try it again as it is not really a practical method, it was fun to try though.
@@HeyBirt carbon rods definitely work and solve the murky water and corrosion problems. They are cheap and easy to find also. Works also when doing electrolytic cleaning of metals.
Thank you so much for this amazing video, as a restorer of machines mainly of old plastics and trying many methods or retro briting, most recently I have Hydrogen Peroxide liquid and 2 x 30w UV lamps to help me and the results have been so good so far. Here in the UK we have very limited clear sunny warm days and I’ve found the cling film and crime peroxide to be a bit hit and miss on causing scarring on the plastics. You video informed of of the science and the myths and felt more like a sped up University course and I truly thank you for taking the time and making this video, Thank You from England and thank you for the education aspect. Forever in Debt to you, Dorian.
When bleaching keys, note that the bigger ones -- the space bar almost always, but it can be others as well like a Big Ass Enter -- may be made of a different plastic than the rest. Typically ABS is used because it's light and sufficiently stiff for such a large key, while the other keys may be PLA, or POM, or something that's easier to make doubleshots with because they melt hotter. They all start the same color, and may or may not yellow similarly, but this explains the differing levels of bleaching required. I know Cherry, in particular, likes to mix POM for smaller keys with ABS for larger ones. Long before any yellowing happens, the ABS keys have their matte finish eroded away by repeated touching in just a year or two, while the POM keys may take the better part of a decade to get equally smoothed over.
Hi Birt! If you ever revisit this experiment one way you can quantify the color change with the equipment you have on hand is to load the picture of the item up in gimp or photoshop and check the RGB or CSV values, recording those each time you take a sample.
Thanks for your work to perform all of these experiments so that we can make some conclusion of how retrobrighting actually works! I am not too knowledgeable on chemistry, but learned a lot and appreciate it.
Hey Birt, I hope you see this comment, as I'm wondering about an aspect of your setup. I'm currently prepping to recreate your 12% H2O2 heat mat setup to do some retrobrighting of my own. I've got a similar setup; same size mat, roughly same size container, the only difference being that I'm using a 30 watt heat mat that has a maximum temperature setting of 45 degrees Celsius. I was wondering how close I could get to the 40 degrees, so I'm testing with tapwater. I've got a polystyrene base with a small sheet of aluminium insulation foil on top to reflect the heat back into the container. The container I've got covered with thick blankets to provide a little bit of insulation as well (not ideal, I know). I've got the heat mat set to 45 degrees, and put a temperature sensor in the water hooked up to a multimeter. After roughly 12 hours the water only gets up to 30-31 degrees with an ambient temperature of roughly 21 degrees. I double checked and the multimeter is accurate. So, for my question to you: I've gone over your video multiple times, as well as the data you've uploaded to OneDrive, but I cannot find if in your tests, by 'temperature', you're referring to the temperature you've got set on the heat mat, or if you've also got a temperature sensor in the hydrogen peroxide. Thanks in advance for answering! It's a really great and insightful video, and an awesome contribution to scientific research on this topic.
I was referring to measures temp of the solution. Note that I did not use a full 12% strength other than in testing. I found that 5%-6% worked well but took just a bit longer. I have a hunch that using string concentrations of hydrogen peroxide might lead to the problem some have had with blotchiness. I have seen this when using caustic chemicals to clean metals. If the cleaning solution is too strong it does not seem to act evenly.
@@HeyBirt Thanks for the quick response! I assumed it was indeed the solution temperature, as that would be the most reliable way of testing. I'll look into increasing the temperature of my test setup, probably by adding more proper insulation to the sides and top of the container. Thanks for the note on the strength. My conclusions from your data was "Well, if it saves a day and produces the same results, better to go for 12%", but if there is a higher (gut feeling) chance of potential blotches, I think it's indeed better to err on the side of caution and take that additional day for a safer approach.
Bit late to the research results you presented here - this is incredible work! Thank you very much for sharing, I enjoyed every minute of your video! I came across the retro computing fascination (61 years old, ZX81 was my first computer, the ZX Spectrum really got me into 8-bit "computing" ;) recently; as Speccies are black, there is no reason to bright them - but I found three Atari's 1024 in a storage room of my research group - heavily yellowed. I am a chemist - and throughout all experiments, research papers, rationals, conclusions, and particular in your case, such nicely conducted experiments, I still struggle with the final molecular interpretation (and I am a bit lost): "Bleaching" is an oxidation process; in case of alkaline "bleach" ClO- + 2e "->" Cl-, and the electrons stem from what was oxidized. Now, my "problem" ;) is that yellowing apparently comes from an oxidation process as well. Why does an oxidative environment such as H2O2, which is a strong oxidizer, not lead to even more yellowing? To be honest, I suspect there is something to the effect of radical trapping into "stable" molecules involved? Radical trapping by uptake of electrons and of course chemical rearrangement (otherwise the result would be an anion) is in essence a reduction reaction caused by the radical nature of the agents - not their oxidizing potential. But I may be totally wrong - I am just starting out with all this - and I am speculating on advertising a master’s thesis project on de-yellowing ... Thanks again, and all the best, Thorsten
Chemistry is not my strong point but I did my best to understand the information I found and interpret the results of the experiments. It is interesting that glass will absorb UVB while letting through UVA. The UVA and/or visible light that makes it through a window increases the rate of yellowing. Though yellowing 'can' occur in darkness. Outside the UVB from sunlight has a bleaching effect on plastic. In either case the sunlight is adding energy, but the resulting chemical reaction is different. UVB is more energetic and as I recall more energetic particles can lead to different results. The use of a bleaching agent like H2O2 results in a reaction similar to UVB exposure and it seem the chemistry of bleaching is well understood. So, this are likely very similar reactions. But like you I don't understand why bleaching instead of yellowing or vice versa. I never could find a good explanation.
Everything that i've retrobrited turned yellow again at quite an accelerated rate, within 2 years.. and the items were not in any sunny or hot location, and away from direct light sources. I've considered if sealing the surface with an automotive grade matte clear coat with UV inhibitors might reduce the return of yellowing..
Thank you for your dilligence in the literature review and all of your hard work to bust those myths! You did an excellent job of explaining this process in a way that was easy to understand and this information is incredibly valuable :) It's very refreshing to see someone approach this (or any) topic with the good old-fashioned scientific method.
Thank you for your great report! I am currently bleaching an old HP Laserjet. Part by part. I can make the following interesting observations: 1. the housing of the printer consists of different parts of ABS, which contain different degrees of flame retardants. From no flame retardants to some flame retardants (ABS-FR) to more flame retardants (ABS-FR30) It can be stated that the higher the flame retardant, the more yellow the parts. Originally all parts had the same colour. The parts without any flame retardant are largely in their original colour. The ABS-FR30 parts are very yellow. 2. at the beginning, the printer stood for 10 years in a room where it was exposed to sunlight on one side through a closed window. These parts facing the sun are more yellowed. 3. the printer was then left in a room without any sunlight for 10 years. Nevertheless, the yellowing has progressed, some parts that still looked good after the first 10 years were heavily yellowed after another 10 years in the dark. I think you have to consider UV radiation depending on its intensity. In low doses, it increases chemical processes such as yellowing. In this case, it acts as an amplifier of chemical processes. In high doses, on the other hand, it has a bleaching effect and counteracts yellowing. There are also reports that unopened cases in their original packaging (sealed airtight) did not yellow in the cellar, whereas the same product in opened packaging in the same cellar is heavily yellowed without sunlight. So oxygen does indeed play a role. Obviously, oxygen and UV radiation have a yellowing effect in low doses and a bleaching effect in high doses.
I suspect that every bit of plastic in consumer items has some degree of flame retardant added. As noted by the NES, different batches of plastic yellow differently. The band of the UV is what determines the bleaching vs. no bleaching effect.
Hey, something I'm having trouble understanding, after watching the video (and I'm hoping you can explain) is: it sounds like heat and UV speed up the yellowing process caused by oxygen... But also the UV from the sun can be used to bleach? So the sun both yellows and bleaches? How do you know which one will happen. If I leave my C64 on a desk facing the window will it get more bleached or more yellowed?
Cool, thanks for these worthwhile efforts, Birt! I particularly like that you noted the potential limitations of experiments (e.g., that you didn't control/measure the room light). Always good to explicitly mention things people might want to control for when trying to repeat. I also liked your rationale for using just (low)heat indoors to control for uneven results. I think I'll use this method if ever I decide to try.
What a great, in-depth exploration of the various approaches (including some novel ones). Living in the Sacramento valley, our summers are very hot and very dry. Humidity is ~30% for about 6 months straight typically. The drought has made it worse. I leverage this, and most work-from-home opportunities, to sun-soak some of my Amiga collection previously brightened (when they need a booster). It seems to keep them in a healthy aesthetic. One thing I've started doing the last year is focused on key caps. Instead of removing them, I'll brush on a 1:2 ratio of liquid oxiclean/water in situ. The amount is light and the hot. dry air minimizes corrosion opportunities. I'll mist, or brush on fresh water periodically (~every 30min) and, as long as I am patient, I can coax the keys back to youth. With brown keys, like the breadbin, I'll carefully apply the oxi solution with a paint brush to the concave area of each key-again, refreshing with vaporized water periodically. This often leaves no perceivable impact to the key's brown color as long as I am vigilant about treating it and the sun is co-operating. Unfortunately, the smoke from the last month or so has limited options on whitening. Thanks again for the great video and interesting research, Jeff.
Thanks for the feedback on the brown keys. It sounds like there is something to using a more dilute solution and being patient rather than a stronger solution.
Hi Jeff. I'm curious if vapor would work also. This, if it works, would reduce the amount of HP to be used. For example a big pan with a lid put on the (induction) stove on the lowest setting. Suspending the knob above the liquid, so the knob isn't submerged in the HP, except for some drops formed on a horizontal surface of the knob. The heat would make the HP evaporate. What are your thoughts ? Thanks for the video.
Water treatment engineer here! Retrobrite is just an advanced oxidation process. In these types of processes, you want to create hydroxyl radicals, which are tremendously potent oxidants. You can achieve this by combining hydrogen peroxide with UV light, as well as with ozone, titanium oxide, and iron in acid medium. This technology is awesome for destroying recalcitrant organic contaminants.
Yes, that was my thesis, Retr0Brite is an oxidation (bleaching) process. Somewhat anticlimactic given many of the myths that has grown up around it but that is what it is and it works.
Hey Brit! I'm curious if you've done any experimenting with the "vapor" method of retr0briting which is gaining popularity. This is similar to the immersion method, but involves placing a small amount of high concentration hydrogen peroxide in a sealed container and exposing it to heat (usually the sun) to induce evaporation. The parts are not submerged or otherwise directly exposed to the hydrogen peroxide itself, only the resulting vapor. Claims are that this uses much less peroxide and results in more even exposure, though may be a bit slower than other methods.
I know of it and have a friend who uses this method almost exclusively, so I know it does work well. The need for sunlight is the only downside. I thought of a hybrid system of a small pool of H2O2 in the bottom of a container and small submissible pump to mist the liquid to cover what is being treated. If the pool of liquid is heated, as I did with seedling mats in this video, you should still have the warm environment and need much less H2O2. I even bought a pump for this but have not built it yet.
I recommend for small and medium size things to use a vacuum sealer that does liquids, pour the peroxide in a vacum seal bag over to the top of the item and vacuum seal carefully in the sink. Then just use a sous vide heater to heat regular water with the vacuum sealed bag inside. This will conserve peroxide and heat evenly without exposing the heater to the peroxide.
Thanks for your great video, Britt! You don't know how many people swear to me that Retrobrite "fumes" causes cancer, that is the primary cause of brittleness, that is dangerous chemicals, etc. Love your scientific approach, did my own animation on my channel a few years ago but your extensive research blows mine away. I have retobrited more than i can remember. Thanks again and let's keep having fun learning new things!
The color of the carrotine molecule shown is not due to its shape but instead it's conjugated pi bond system. The center section consisying of a line of double bonded carbon atoms is special. Thrre are two kindsbof bonds, sigma bonds and pi bonds. The sigma bonds are localized between the carbon atoms. The second bond, the pi bond, is not. The electrons takig part in the pi bonds can move throughout the entire conjugated pi system. This is a common theme in organic dyes. Six membered aromatic rings can also take part in these conjugated systems. Many organic systems owe thtir golor to these sorts of conjugated bonds. Inorganic compounds typically owe their color to ansorbtion of light by the outer electrons. Examples of these are colored forks of oxidized metal ins in solution. Som compubds have distinctive colors in their unoxidized states as well. For example gold and copper. Bromine and iodine also have distinctive colors in their ground state. Iodine is purple and bromine is a redish brown. Unlike metal atoms, which oxidize to a positivly charged state by losing an electron, bromine will reduce to a negativly charged state or can take part in covalent bonding. In the absense of other factors, solutions if negativly chatged bromine ions, or compounds containig covalently bonded bromine are colorless. However, bromine solutions are well known to turn yellow over time. This is caused by the bronine losing an electron, and going from its Br-1 reduced form to the +0 form which consists of 2 Br+0 species covalently bonded. This is accelerated by exposure to oxygen and light. Another reaction that is common is that a photon of light os absorbed by the carbon halogen bond in an organohalide. The halogen is removed and grabs the hydrogen from tfe neighboring carbon, leaving a double bond. This is the opposite of such an acid adding across a double bond and creating an organohalide. Depending on the encotonment, hydrobromic acid can also further go on to create molecular bromine (consisting of 2 bromine atoms covalently bonded). The double bonds which can take part in conjugated pi bond systems should neighboring atoms also have such bonds can easily create absorbtion bands in the plastic that could cause yellowing. Its also possible that residual Br2 could build up and cause yellowing. Hydrogen peroxide and light creates free radical spevies that are highly reactive. They are commonly used to intiate various reactions. For example, peroxides or light, or both are commonly used to intiate polymerization rezctions. They are also used to intitate ractions of halogens like bromine. Free radical reactions involving peroxide, light and halogens are commonly used to add halogens to species with double bonds. Doing so to one that takes part in a conjugated pi system would alter its absorbtion of light. So bromine taking part in both the yellowing and bleaching of plastics is not at all implausible. There are other reactions that free radicals can cause as well that might remove and create yellowing as well. The fact (as is well known) that plastics sitting in sunlight yellow much faster than NOS plastics sitting in a box, but even plastics stored in a dark place yellow, and that its also accelerated by ozone, suggests that oxygen AND light are involved. Bromine plausibly yellows plastics over time by multiple mechanisms. But just because non-brominated plastics also yellow does not suggest thd bromine plays no role. Different plastics may yellow or whiten by slightly different, or vastly different mechanisms. Its also the case that some substrates are resitant to yellowing, and others do not brighten with peroxode and light.
Thank you very much for the video. I have wondered about the yellowing of plastics for years. I found this video through a support group for TRS Model 100 computers. I am a 71 year old retired Mechanical Engineer. My Counselor says I am a Researcher. Since a good Mechanical Engineer can do anything, and I am a Researcher, I was able to follow everything in your fantastic and extremely informative video. There are so many great takeaways. Question: How long did it take to make this videlo?
What doesn't make sense is that I had stuff in storage for nearly 10 years in complete darkness and cold temperatures, and my SNES, the SNES mouse and a Ghostbusters car all turned yellow.
What a wonderful, in-depth video. After looking around at all the myth regarding retrobrighting I couldn't get a handle on how it was supposed to be working. Your video and research has made the process very clear. Thanks for all your effort and true scientific analysis. Now all I have to decide is, do I really want my yellowed plastics white again?
I loved this video, Jeff. I'm curious if the 7% H2O2 I see on Amazon for water systems would work the same as the 6% solution. It doesn't have any other ingredients beyond the peroxide and water, so I don't see why there would be an issue but I would like your thoughts on it.
I don't see why it would not work. Compare the price to getting the 12% from a local beauty supply store. Around here that is the least expensive option.
I think that it has been demonstrated that heat without light is a good enough 'energy source' for the Hydrogen Peroxide to do its thing. UV light is not necessarily required. A case brushed with Peroxide Cream in a zip lock bag in an oven at 50 degrees that is brushed periodically (approximately every 20 minutes), with the reapplication of cream as required to stop it drying out or crystallising, has been demonstrated to work well. Any thoughts on this?
Light and heat both add energy to the chemical reaction so either will work. The problem with using UV light and the cream is the potential for a streaked result. Most household ovens do a very poor job at temperature regulation, so it is advisable to measure the actual temp in the oven with a precise thermocouple. You might find you the bottom of the part near the heating element gets much hotter than the top or side. The advantage of using immersion in dilute H2O2 is that the temperature is consistent. Check out the video I did a few months ago on a VIC-20 that was the color of cheddar cheese. For fun I left it in the Retr0Brite bath for 7 days.
there is a question seems nobody yet answered. What is the change in the plastic strength, both from yellowing, and later on retrobrighting. do we get back the strength before yellowing, or do we worsen it altogether? I can think of trying it using printed ABS with rapid yellowing thru heat and oxidation to compare with a part that has been vacuum sealed and another part that has also been yellowed but retrobrighted later on.
Both the yellowing and Retr0Brite process are going to have a minute negative effect on the strength of the plastic. Only in extreme cases of yellowing will the integrity of the plastic be compromised. The Retr0Brite process will not restore any lost material or strength to the case. Since there are so many variables, i.e. the exact mix of plastic, the amount/length of UV exposure, exposure to high heat, etc. it is impossible to generalize as to length of exposure vs. amount of damage. That would only be valid on one type/mix of plastic. The plastic mix for 3D printing is not the same as used for injection molding. They are designed for two different processes so it would be hard to compare UV effects on one to the other.
@@HeyBirt well that's the thing. In simplified terms, let's say yellowing makes compound A become compound B, and from evidence it seems that the higher the concentration of B in the plastic, it appears to be more brittle. However we don't currently know if any of the bleaching processes are making compound B become compound A again (a possibility), therefore returning the strength to the material, or making B become C, and in this later case, if compound C is more, or less, strong, than the original compound A. Obviously 3D printable ABS is not the exact formulation as injection molded ABS, yet it is similar enough to serve as a starting experimentation point, as the differences would not be so drastic as say, comparing ABS with PETG or PLA or any other plastic. Indeed as you said yourself, every manufactured ABS is different, so by testing with printable ABS we're most probably in the same amount of difference than using any ABS, as the formulation is never going to be what Apple, Commodore, or Nintendo used 30 years ago. Don't get me wrong I think you've done an amazing work with your video, I'm just thinking on what the next steps could be without, as you said, the "expensive" (and let's not forget, difficult to get) equipment a proper lab would have (that could even formulate more precise ABS variants). That's why I suggested 3D printing as a doable next step.
@@TinkeringDaemon The problem is that not even all ABS is the same. It would be near impossible to make a generalization about what effect a certain exposure has on ABS brand A will have on any other brand. There are many, many papers written about photodegradation where they go into detail about the various plastic mixes (different formulations of same plastic type or different plastic types) they use and how they were exposed. You can infer some general characteristics from these tests, i.e. UV exposure is harmful, but you can't conclude that since Plastic A performed a certain way that Plastic B will do the same. This is one of the reason that there are standards that products are tested against. That is the only way you know a material meets certain properties, such as resistance to UV damage. These sorts of tests are well beyond a home workshop though.
Thanks for this very informative video, debunking the bromine nonsense and showing what retr0briting does to the plastic. In the LEGO community the yellowing of white and grey ABS pieces due to UV light is considered a pretty big problem without a permanent fix and many report that even sets kept in a dark basement undergone yellowing. I have tried the 12% hydrogen peroxide + UV light activator method many times but sadly the "bleaching" is only superficial and temporary and after a few month the parts will be yellowed again even if kept in the dark. What I did not test is storing the treated parts in an airtight container + refrigerator and check if the oxidation is slowed. I also noticed on my white NZXT Phantom computer case, that the rear top area where the most heat gets accumulated caused very strong yellowing so UV light is not even needed to cause damage. Wish there was a permanent solution to reverse the yellowing because my expensive LEGO Star Wars sets look horrible and are now pretty worthless.
If I wanted to try the immersion with heat method but I already bought the 40V cream at Sally’s…could I just put the cream in the water and stir it around in it so it dissolves?
You can dissolve the cream in water, I have done that in the past. It does not store as well after you are done though. With the liquid I can filter it and store it in a large plastic jug for months to use again. It does loose it potency over time though.
Thanks, a bit too much for now, so it is in Save for later for a re-watch. I have to say I go for sunbrite nowadays, as it is very easy to do, and almost as succesful as previous messing with chemicals.
My hypothesis: Epoxidation followed by Hydrolisis. Water acting as an acid here. It "changes" the conjugated system of the chromophore. "more double bonds => more absorption => colorshift to yellow", a bit simplified... I suggest you use Sodium sulfate as an electrolyte. Should be safe. That's all i can add, it's been years since Uni or working in the field of chemistry. Nice work, thanks!
What doesn't make sense to me: If the process that causes the yellowing is oxidation and the process by which the bleach works is also oxidation and if that bleaching process is what works on the plastic parts, then we are not reversing the yellowing process. We are oxidizing already oxidized material. Oxidation isn't like subtraction, where to negatives make a positive. The reverse process of oxidazation is reduction. So: what is indeed happening?
...Not only should the oxidation by the bleach not reverse the oxidation that caused the yellowing, it should also MAKE more yellowed material, as we stated earlier, that oxidation is what leads to the yellowing. So: one of the processes needs to involve reduction or what is happening is not a reversal but a further transformation and probably destruction of the oxidized material. Something is not adding up. Can anybody help cleat up this contradiction?
What's with that asymmetric colour wheel at around 3:30? Why the size difference between some of the pie pieces? The colours are odd too. From orange to orange-yellow to orange to red - why?
@@ropersonline But it served its purpose of showing a lot of different colors, that is all it was used for. The next slide shows a proper spectrum which also relates color to wavelength...
Such a relief that you didn't come out with anything that went against what had already been shown to probably be true! Now we can actually know these things are true rather than just suspect it. Someone had told me about using an auto stirring heated flask setup along with hydrogen peroxide and TAED a couple of years ago and said how effective and controlled it was and this is the first time I've heard it being talked about since.
@@HeyBirt The only thing I think you didn't touch on was Neil's sous vide method, which stirs the water as well as heating it to a preset temperature. That may be better than those pads - although the stick is more expensive to start with. Again though thanks!
It is accomplishing the same thing, a consistent heating of the liquid. Neil sealed the parts in bags of H2O2 to avoid forcing the sous vide from having to pump it. The sous vide machine pumping the water is a side effect of how it works, i.e. pull the water through to heat it and distribute it. The heat mats heat the entire under surface of the container so not as much to be accomplished w.r.t. heat distribution. Agitating the liquid H202 might help speed up the reaction though by ensuring a more homogeneous solution throughout.
When I go to add a comment and find that someone else has already written it for me. Then I look at the composer to find it’s someone I’ve already got a deep respect for. So all that’s left is to thank Hey Birt! For such a great and insightful video. The heated mats are a great idea, I’ve been using a brewing immersion heater (purely because it was something I had to hand) which can only get to about 34c.
@@HeyBirt Yes. That means the 3 most successful/reliable ways to do it in my subjective opinion are your heat pads, Neil's sous vide and Kai's heating mantle. And they're all essentially the same method at heart.
Now I wonder if there is any scientifically explained approach to restore black plastic. Among all the black console restoration videos on TH-cam there seems to be no solution aside massaging all kinds of greases into the surface or a heat gun treatment to make them look new. But do one of these actually work and if yes how?
I guess it depends on how the plastic has been damaged. The sun will have a bleaching effect on the black pigment, there is no way to prevent that. Various topical treatments, the 'greases' as you call them, help to improve the appearance and many will help protect from further UV damage. I like to use 303 Aerospace protectant for this purpose. The heat gun trick is an old one and just remelts the outer layer of plastic. You also stand a very good chance of warping and burning the plastic using this method.
So if Retr0bright is essentially a bleaching process, should we be using it on plastics that are intended to be colors other than bright white? Or, what are the best practices we should be following when working with colored plastics? I'm thinking largely of things like SNES cartridges, which have a medium grayish-blue for their original color. I also have a Famicom cartridge that was originally bright blue, but has turned a lovely green along some surfaces.
We are all used to the Chlorine bleach used in our laundry having an adverse affect on colored cloths. This is more of an issue with the dye used. I add a little Chlorine bleach when washing my white cloths and it does not harm my white tube socks with colored stripes. The Retr0Brite bleaching process is not really turning something white per say, it is turning it less yellow, i.e. breaking the double atomic bonds shifts the reflected light away from yellow and back to closer to what the original color. Some colored plastic does seem to have problems, from what I have seen this mainly seems to be with the brown plastic over white plastic key caps. When trying to Retr0Brite the white plastic lettering sometimes the brown will splotch. It is hard to know if this will happen until you try. This might be a case where sun bleaching is a better option.
Those 20W heat mats only [barely] raise the liquid 20F over whatever the ambient air temperature is. (Remember, these are intended for supporting seed germination.) If it were room temperature inside, the highest temperature the liquid would be -- with the heat mat on its highest setting -- is ~90F. Are you sure this is enough for retrobright? It seems to be that the pieces would need to be submerged for a matter of several days. I feel as though the best thing to do (at least, in a warmer climate) is to put the container outdoors and in the shade, while having the heat mat underneath as a supplemental heat source. It would be ideal if the outdoor temperature is 85F+ in the shade.
You will notice I insulated around the container which was enough to raise the liquid temp to 38C to 40C. I also compared the difference in time at various temps/concentrations of H202. The point of the heat mats is it lets you Retr0Brite anytime, any season, in a controlled manner.
@@HeyBirt Hey Birt, thank you for pointing that out; it seems I had looked over the section wherein you talked about insulating the container with cardboard and foam panels. I would be interested in trying the same, as I'm working with an indoor ambient air temperature that isn't particularly warm. Granted, to eliminate as many steps as possible, a stronger yet similarly controllable heat source would be nice to have. I've seen at least one person have success by using a sous vide for retrobright, so I may look into that and determine whether or not it can sustain a reasonable temperature within a large container that has no additional insulation.
@@icantgivecredit871 It is very important to be able to precisely control the temperature. If you get the liquid too hot the plastic parts can warp, even well before you reach the glass transition temperature. I suggest aiming for no more then 50C. I chose 40C to be well on the safe end of things. There is no reason not to insulate the container. Even a simple cardboard box over the top of it works wonders.
@@HeyBirt Okay, I'll ensure it doesn't go any higher than what you specified. I'll likely buy both the seedling mat and the sous vide, so I can gather findings on each. The sous vide is more expensive, but it should cut the treatment time considerably. (The sous vide has a precise thermostat as well.)
Soo, ive seen people use UV lighting, mixed with HP and heat. Another vid says the UV light isnt needed and doesnt make sense, since it was UV light that damaged it in the first place, and it only causes it to yellow again in a few days. So are you saying the UV light doesnt cause it to yellow again soon after, and that no matter what, unless you spray protection on it, anything can yellow again in a few days?
I came here looking for a more scientific approach, and I am very impressed and thankful for the time you spent on this. It's also clear now that the different techniques may be selected as much based upon the part being bleached as it is about the speed of the results. Thinking of my collection, I can see that some techniques may be needed for different components. My IBM PC340GL case has a metal shield permanently attached to it which is not going to do well submerged in peroxide, the creme/film technique risks the "marble" effect, so maybe that's just a "sunbrite" with regular rotation and just accept it will take more time. The drive bay covers and front plastics can sit in peroxide on a seed mat indoors and do just fine.
Note: I learned about the damage peroxide does to metal when I tried to 'weigh down' a case with multiple big washers screwed lightly into the case standoff - trying to prevent the accumulation of bubbles from causing the parts to float. The washers 'rusted' and I had to clean the new rust stains off the plastic...
I have found that aluminum, brass and copper do not seem to be affected by H2O2 at all. If steel is chrome plated it hold up well, common zinc plated steel fasteners will rust.
Thank you so much for this thorough research project, I'm looking to retrobright some of my own electronics, and this video provided a lot of great info and a fantastic method for me.
Hey Birt, putting this to the test. I just put out a table full of Keyboards and Amiga case parts that are badly yellowed. I will give them a few days and report back. I LOVE the idea of a way to de-yellow plastics without any environmental impact whatsoever!
I have had a GBA glacier color shell in a 3% hydrogen peroxide bath and sealed UV light box for half a month with no noticeable change to the yellowing. Anyone have any idea why? I was hoping this video gave more insight but am still confused.
As shown in my test results a 3% solution is very slow acting. Hydrogen peroxide breaks down with time and the process is sped up with exposure to light (which is one reason why light helps speed up the process and why H2O2 bottles are brown). If your 3% solution was old, it may have already been partially decomposed. There is a great difference in the quality of the various UV 'grow' lights sold today. I would not be surprised to find that one claiming to be a UV source really is not. The water itself will block some of the UV. As I mentioned in the video, I think the heat mats are the way to go. It is a very controllable process.
Bleaching agents (chemicals) do not all react the same with all materials. Industrially you will find that different bleaching agents are used for paper than clothing, etc.
yes, but I'm not sure how the suos vide would hold up to the H2O2. Perhaps placing your plastic and H202 solution in large plastic bags then put the bags in a tank of water with the suos vide?
Great video, how long did the heated water method take you? Will it take any text or colors that are supposed to be on the plastic your treating (in my case knobs with colored caps) off in that method?
The amount of time depends on the plastic, amount of yellowing, concentration of H2O2 and temperature. With a 6% concentration at 40C it took about 2 days. Sometime with dark keycaps with lighter lettering (two shot injected, i.e. the letting is white plastic the key body brown plastic) the dark plastic might blotch. This depends on the exact plastic used.
@@HeyBirt thanks for the response! I’m wondering if the cream and UV might work better for my knobs... I’d like them to go back to original Grey and ideally not loose any of the color on the knob caps... and ideally, within a 4-8 hour time frame.
@@HeyBirt the plastic isn’t drastically yellowed, but certainly noticeable. I believe it’s painted acrylic.. when you say concentration of H202, are you referring to the ratio of water to the Salon Care 40 (clear), or do you use the SC 20 or 30? Thanks for you help.
@@Musinformation96 If it is paint then H202 will not do anything. If you have SC40 that is 12% H202. So if you mix 1L of SC40 and 1L of distilled water you will have a 6% solution.
Excellent video! I was wondering if you had any information on the unusual non-yellowing plastic that was used in IBM PS/2 computers (at least in the early models). I have a 32 year old IBM model M PS/2 keyboard that looks the same as the day I got it as my 16th birthday present (sadly the old 286 system it came with is long gone - I kept the keyboard because I loved its typing feel). Every other classic "various shades of beige" computer component I own has yellowed but the old IBM keyboard seems utterly impervious to yellowing or showing signs of age. That thing is the Dorian Grey of my computer collection. Was there something special in the formulation of the plastic IBM used and if yes, why did this not become common (cost? toxicity?).
@@nickwallette6201 It's a keyboard and no, it's not got a weird coat of paint on it. It's just molded plastic with a lot of metal internals. Old Model M's were designed to imitate the feel of typing on an IBM Selectric typewriter. The thing is incredibly heavy and durable. The plastic used in them is known to not yellow (or if it does yellow, the process is incredibly slow or delayed by many decades). I have seen it discussed in other videos and have visible evidence sitting on my basement shelf. My other "antique" mechanical keyboard is a 21 year old Keytronic model that started roughly the same tint as the IBM and has been stored with it for a few decades... only the Keytronic is almost banana coloured now but the IBM just doesn't change. It's something about the plastic composition IBM adopted for that line. It had some downside which caused it not to be broadly adopted and later dropped by IBM. A bit of digging suggests that IBM used a different types of plastic from the common type (PBT and possibly something else instead of ABS) and most users report little to no yellowing to this day on IBM plastics from that era. If the sources I found are correct, they don't have a fire retardant agent in them that tends to accelerate the yellowing process in addition to being different plastics. Presumably they will eventually yellow but they just seem to be doing it very slowly in most cases.
Yep, I have a Model M. And two Model Fs. And a whole pile of PC/XT/ATs, PS/2s, a PS/1, a PCJr, some RGB monitors...etc... I don't have my Model M out right now, so I'm not 100% sure. But, a lot of that other plastic is painted. I made the mistake of taking a Magic Eraser to my 5151 display enclosure and got right down to the bare plastic -- which, FYI, is not beige... in case anyone's wondering. :-)
Very interesting! I was looking forward to a scientific explanation for the effect of hydrogen peroxide for a long time now. Retrobrighting is great but the next step would be to figure out how to protect the ABS plastics from the oxygen corrosion. I wonder if a clear anti-corrosion spray would work well on plastics as it does on metals. Together with UV protection that would shield the plastic from harm and stop (re-)yellowing.
A product like 303 will help as it has a UV protectant and it coats the surface limiting exposure to the air. You could spray a clear coat on but that might alter the texture, etc.
How can oxidation both cause yellowing and brightening? It doesn't make sense. Plastics on electronics spend most of their time in-doors where there is a substantial lack of UV-light. What there is more of, is heat, and other gases. Plus reduced ventilation. On the other hand, I've seen people brighten plastic with just heat. My theory is that yellowing of plastic is caused by "low" oxidation over time. If that's the case, storing your plastics in-doors, and especially inside containers, will cause yellowing over time, and that a UV protectant might actually contribute. When putting yellowed plastic in an environment where oxidation is not just "normal", but "high", you compensate for the long period of "low" oxidation, but some damage might already have occurred. Oxidation is increased with light and/or heat and/or chemicals. The cheapest, simplest option seems to be to place the plastic outdoors on a not-too-hot sunny day while ensuring even coverage. Have I tried it? No.
Sunlight has three 'bands' of UV cleverly named UVA, UVB, UVC with UVA being the longest wavelength and least energetic, obnoxious and dangerous. Earths atmosphere filters out UVC which is great for us. Regular window glass filters out UVB, you get get a sunburn indoors. About 75% of UVA still gets though and causes the yellowing to occur. Fancy modern windows might have UVA blocking film applied to the glass as well. When you are whitening the oxidation process is working on the yellow chromophores. This is true is you are using hydrogen peroxide or the sun. When plastic is outside and exposed to UVB it gets bleached.
Have you considered humidity as a factor? It seems like in many cases, when these electronics are kept in humid basemants, the yellowing is more pronounced.
I have not seen anything to suggest that higher humidity levels increase the rate of yellowing. New plastic that has been kept in a dark cool place can still yellow. Exposure to higher temperatures and/or UV increase the rate of yellowing.
What a thorough, exacting treatment of the subject. Thank you for your exhaustive work. I'm looking to try this out myself, following your preference of 12% liquid hydrogen peroxide submersion and a heat pad only. Do you have any guidance on about how long the initial submersion should be for? If you said that in the video already, I apologize for missing it. Thank you
There is not set time for treatment. Check periodically and take out when it looks OK to you. The more yellow the plastic is the longer it will take. Also keep in mind that it seems to work faster at first, i.e. it will take longer to get that last little bit of yellow out. Having something to use as a comparison for the color change is helpful.
As somebody who went through a punk phase in college, it seems completely obvious that hair bleach, when applied to yellowed plastic, bleaches the plastic. I do think it probably does damage the surface layer of that plastic, rather than returning it to its original state, but it's probably a very thin layer (the same few microns that have yellowed). It might speed up the rate of wear from typing, but it's probably insignificant compared to just using the keyboard another year. And if it is for a museum or collector's piece, the aesthetics are probably worth it.
Yes, the Retr0Brite process does indeed have some very minute effect on the surface layer of the plastic. But as you point out so does using the computer, or wiping it with a cloth, handling it, etc.
Yes, it is bleaching. If you go too far/long, it will become lighter than original. I have over-bleached keyboard keys by leaving them in heated peroxide for too long.
Good point, all things in moderation. The plastic used for the key caps seems to react a bit different is many regards. One of the benefits of 'slow cooking' using the heat mats is it is harder to over cook something.
@@HutchCA I suspect it is sufficient to change only the surface to a few microns to change the perceived colour. One could experiment by "over retrobrite-ing" a piece of plastic and then slicing it to see if the colour change penetrates, or try it with a yellowed piece of translucent plastic and see if it can be made totally clear again.
I tried retrobrighting twice - one success, one blotchy mess. The interesting thing is I was using the "wrong" chemical. I used Draino/Sodium Hydroxide. That's another case for the bleaching theory.
The lye will clean it for sure but will also probably damage the plastic as you found out. Sodium Hydroxide does work wonders for high resistance conductive rubber key contacts though. I have another video on how to revive them.
I would encourage anyone to go ahead with retrobriting. Sure, it's possible it might not look good when you're done, but IMO, it doesn't look good when you start either. So, what do you have to lose? The vast majority of my stuff has turned out anywhere from "well, that's _better_ I guess" to "perfect!" with very limited negative outcomes. Namely: * A couple CD bezels that lost too much intended yellow and started taking on a reddish-gray hue (Creative [Philips OEM] CD bezels.) * A front plastic bezel on a desktop PC case that took _FOREVER_ and didn't completely bleach all the yellow, but also whitened too much, and is now a splotchy albino beige. (I overcooked this one -- further proof of the bleaching process? -- and it also spent a lot of time floating up to the surface, i.e., not submerged.) * Some screen printing loses some of its saturation (Creative and Plextor CD bezels, mainly), but this is fairly rare. Most screen printing is perfectly fine. * Anything painted has a chance of becoming un-painted. Happened to a case badge with a painted background (totally dissolved the paint and is now bare metallic), and the inside of a transparent plastic sticker on the MHz display / button legends of a mini tower case (some spots of lost color.) To avoid: Anything painted should be removed, if possible. Don't carry on too long -- if it doesn't work within a reasonable amount of time (relative to your process and other results), then call it quits and take what you can get. I personally prefer submersion in liquid (store-bought 99c antiseptic Hydrogen Peroxide bottles, because it's easy to get hold of -- provided you're not in the middle of a pandemic), and use a couple 30W UV LED panels, but if heat works as well, that's probably better. So, to sum up, in the worst case, it doesn't turn out well and you will need to paint it. How's that any worse than looking like a smoker's lung? :-)
Going to 70C for the bleaching process should not be any problem, as ABS is a thermoplastic and stable to above 100C before any softening occurs. So using hot water and UV light together with hydrogen peroxide should be ideal then? Did you test all that together to see how the combined effect worked?
The 'glass transition temperature' of ABS is about 100C but you have to consider what that term means. It is the midway point between the solid glass state and rubbery state, by the time to reach that point the material is already quite reduced in strength. We also don't know exactly what is in the plastics we are dealing with, as pointed out a high impact ABS will have a lower glass transition temperature around 85C and a maximum service temperature of 65C, i.e. above 65C it should not be used continuously as it is already weaker. This latter term gives us an idea of how reduced in strength the part is well before the glass transition temperature. You also have the issue of large items like a space bar distorting as they heat unevenly. Also as mentioned the surface temperature of your container may be well above the liquid temperature. Also consider that above 50C is considered a 'scaling temperature' and should be approached with due consideration for safety.
@@HeyBirt Absolutely, but a key in a tub is not in use, or really put under any stress.. So according to above you can go to 65C no problem. And if you cover the outside of the vessel in aluminium foil you basically have an all round mirror, the uneveness in the foil add to the light dispersion also which pretty much removes any chance of uneven light. Any remaining factors are pretty much those that you learn in science as "minimal impact" and round off to 0. :D ABS is easy peasy to restore.. Try 50 year old computer cases with a foam sandwich construction that litterally breaks on touch.....
@@MrZnarffy It's put under the stress of its own dimensional stability, and gravity. I would suggest not relying on intuition, which is often based on circumstantial evidence that may or may not be relevant. Take something representative, but not valuable, and give it a try. Many people use hair dryers to soften old plastic to prevent breaking pieces that have become brittle with age and natural loss of plasticizers. What do you think the temperature is coming out of a hair dryer held six inches away from a surface? If, at that point, the plastic is already becoming malleable, consider how it would fare at that temperature for a prolonger period (hours, or a day or two) while treating it.
@@nickwallette6201 Not talking hair dryers.. I got experience working with ABS, since I'm a biker who likes speed, and bike fairings easily cost $1000 per piece. And 3d print in ABS as well. You know you can dissolve ABS in acetone for example, and when the acetone evaporates, you have solid ABS? The stuff I have issues with is 50+ years old sandwich constructions of some kind of styrene foam and abs... me and my mates call that "fragilium"....
@@MrZnarffy I don't quite understand what point you're trying to make. The point I am making is that it seems you can soften ABS considerably by using a hair dryer. It's difficult to say what temperature, exactly, that air will be (since it's not often regulated - or at least not user-controllable), but from what I can tell, a hair dryer's average air temperature is more like 55-65C. That suggests that it's going to be solid, but malleable, at far less than 100C, with the potential to change shape under normal atmospheric forces. I don't know what acetone has to do with this, since that's a chemical reaction, not externally-applied heat.
Excellent work Jeff! In your next video, can you keep the text cards on screen longer? Some of the more text rich slides were very difficult to read when they were on screen for only 1-2s.
Sure. Thanks very much for the feedback. It is hard to know how to strike a balance at time. I currently have them set to 2s but can up that to 4s and see how that works out.
I use sunbright on all plastics, usually it works but not as well as the peroxide method. A faint yellow taint is still present on most of my projects, but no chemicals has been used , so it is a big plus environment wise.
As a chemist, here are a few thoughts:
1) Of course it is a bleaching process.
2) Sunbrithing probably works because the Chromophores are more susceptible to Photooxidation than the bulk plastic.
3) Hydration (Addition of Hydrogen) with H2O2 sounds like BS to me.
4) The electrolysis isn't likely to work in it's current form, because elemental Oxygen and Hydrogen aren't very reactive at Room Temperature (RT). The most likely bet is if the plastic part itself acts a an electrode (hard to implement due to conductivity)
5) As you said, the corrosion of the Anode is a well known problem in Electrolysis. The safest way to prevent this is to use Nobel Metals like Gold or Platinum at the Anode. Silver, Titanium, Lead or Carbon may also work. Lead (IV) oxide is often used for this in industry. Corrosion at the Anode is very dependent on the pH of the Electrolyte and Current density. The blackening of the Cathode is likely due to dissolved Anode matter being reduced at the Cathode.
6) Using Sodium Chloride as an Electrolyte is a bit dangerous, as it can lead to chlorine formation. This might work to bleach the plastics at the Anode though.
7) Hydrating the Plastic with Hydrogen is unlikely to succeed, this reaction is usually done in solution with Palladium on Carbon as a Catalyst.
8) The most amateur accessible method to hydrate the plastic surface could be using tin in hydrochloric acid. This will form SnH4 which might react with the Chromophores. Other reagents could be Diimide (made from Hydrazine and H2O2) as well as Sodium Borohydride and Lithium Aluminium Hydride. The later two are unlikely to react with the double bonds in the Chromophore (unless these double bonds are Michael acceptors), it could still have an effect on some functional groups that could improve (or worsen) the situation.
9) H2O2 decomposition can be catalyzed by adding Potassium Permanganate or Dichromate in very low concentrations. Copper sulfate could also work. These salts can leave a stain on the plastic though.
So what would be a better permanent solution in your opinion? I've heard retrobrite doesn't last forever
Slightly pedantic, I think you might mean hydrogenation, or hydroxylation, rather than hydration
Hey Birt! So, I watched the whole thing before commenting. You do keep saying that there is no way to stop the oxidation process. But there is. You touched on it at 34:12, but I felt you should have elaborated on it. People often ask me if there is a way to prevent yellowing and I will say to remove the oxygen. Even covering something in plastic wrap or aluminum foil is helpful as it keeps out fresh oxygen. But a vacuum sealed bag probably works best, or possibly a bag filled with nitrogen, CO2, or some other inert gas. On interesting anecdote is that I have an Atari ST that has yellowed significantly around the power supply from heat. But there was a paper sticker on the plastic in that spot. Removing the sticker revealed no yellowing underneath. Since heat was the catalyst here (not light), clearly the sticker didn't prevent that area from becoming hot. So the only conclusion is it stopped fresh oxygen from contacting the plastic.
I would also comment about Sodium Percarbonate. It does work very well for retr0brite. But, as you mentioned, it is very alkaline. I destroyed a Macintosh LC top cover using this stuff because it ate away the RF shield, which unfortunately cannot be removed from the plastic. But the plastic itself came out looking great. So as long as there are no metal parts, the Sodium Percabonate may even be a better choice as it is easier to store, I think.
Hi David, thanks for your thoughts. On the subject of preventing re-yellowing the paper that Perfractic found a few years ago outlined some very interesting experiments. After weathering the samples they were wrapped in aluminum foil and kept at -10C and they still yellowed. However, they whitened up again just being out in the normal daylight through a window.
This correlates with anecdotal evidence reported by some in the vintage computer community that even when wrapped up and in the dark some items yellowed a bit. The last video GadgetUK did he noted this with his A1200 which had been sitting in the corner of a room for a few years out of direct light, it had darkened up a bit but after a few hours in the garden and a few days of using it whitened up again.
The oxidation problem can be reduced by all the methods you describe but there is still this other phenomenon that can happen and it does not seem to be preventable. From what I can tell it has something to do with certain molecules coming into equilibrium in different configurations when in the light vs. when in the dark.
It doesn't make sense to me that you can fix a problem caused by oxidation with oxidation, unless it has to do with the amount of oxidation. If stored in-doors, and especially in a container, the amount of oxidation is low. If you put it out in the sun, the oxidation is high, and you can reverse the effects of low oxidation to a certain extent. The sticker example is an interesting one, though. What if the explanation to that one isn't the lack of oxygen, but the adhesive and sticker itself?
I think heat is a greater contributor to yellowing than light, and maybe the idea about the reason being light was due to the fact that heavily yellowed plastic often has been placed in a window area. Yes, there is more light there, but also more heat, from the sunlight or an actual heater. Window glass, at least nowadays, blocks a lot of UV-light.
The only problem with storing your devices in an oxygen free environment is how hard it makes them to use while stored. HAHA..
Re: Yellowing in light vs. dark, there's definitely evidence of both cases. E.g., I have some large computer cases that obviously yellowed more where exposed to light(?), in that a certain side was lighter or darker than another, and if something (a monitor, e.g.) sat on top of the case, the area directly underneath was less affected.
In contrast, Plextor CD drives have a tendency to yellow quite a bit. I had a couple of SCSI drives that I used back before SATA -- maybe had them installed in a case under a desk for a couple years in a room with some ambient light through a window, but nothing direct. I then put them in a shoebox and kept them in storage, partly in a garage that tends to stay cool (50-65F in the winter due to a heater, 55-70F in the summer due to northern climate) for about fifteen years, and they turned _quite_ yellow during that time.
My supposition here is a rather pedestrian one: It varies a lot, presumably by the type of plastic, and whatever colorants and treatments they use. I suspect there is more than one mechanism at play, and any blanket statement that "it's light" or "it's heat" or "it's just oxidation" probably applies to one or more, but probably not all of those cases.
Just a side note, I wouldn't try CO2 as a gas for preservation. It's actually acidic. Generally you want to lean toward the basic side of things for preservation. A lot of museums look for acid free, and buffered (doped with a base chemical, like baking soda) materials to help preserve things. This assumes the item itself isn't so acidic that it will be harmed by reacting with a base, of course.
Excellent info! Thanks for all the hard work.
I would advise against using table salt as electrolyte. Electrolysis of saline solution can produce chlorine gas.
Thanks, that is true.
I tried electrolysis of salt water, I had it outside but in a covered area, so chlorine gas would harmlessly dissipate, however NaCl + H20 also produced NaOH (caustic soda) and leaving overnight with 12Volts at 1Amp produced so much NaOH it not only ate the electrode but also the alligator clips connected to them.
In aqueous solution it produces liquid bleach...
Maybe it’s time for a Nile Red collab and explore the other options you mentioned? Thank you for the video!
@D. A. Respect your elders you young whippersnapper :)
Megulars pour tableau de bord de voiture
Excellent work Jeff! I observed most of the effects you described 1:1 during the course of my own retrobrighting experiments over the years. Turns out I had only very vague ideas about the science behind it though. At least I stopped blaming the Bromine pretty early on after reading up on it. ;) Thanks for this video, hopefully it's going to help clear things up and the future is going to look a bit brighter... ;P
Thanks Jan, it was a lot of work but a lot of fun too...
Jan, I can't help myself. I'm hearing your comment in your actual voice. xD
@@Starchface same!
@@HeyBirt - I've been doing retro-brighting for many years by simple trial and error. heh While I just found this video, most of my methods are similar with some differences which might help you, especially the HCl activator method.
Here are some tips for improving retro-brighting making it better and faster.
Before you start, it's highly recommended to wash all the parts using a nail brush with soapy detergent like dish-washing liquid and warm water, then rinse it several times with clean water to get rid of any residue, which will help the bleaching process to be more even. Using peroxide cream is relatively weaker than peroxide liquid (also in higher concentration), and tends to leave shadow lines due to uneven coverage. I recommend using a standard Rubbermaid/Hefty or similar plastic storage tray at least 5 inches tall, and long and wide enough to fit your largest parts.
1. Use a 20-30% peroxide liquid available at swimming pool supply stores sold as "Pool oxidizer/disinfector" in one gallon jugs (about $30usd/gallon).
2. As a common bleaching activator, add a quarter cup of TAED (Tetra-Acetyl-Ethylene-Diamine) to each one Liter (quarter gallon) of peroxide. TAED is available online as powder and in some OxiClean formulations (read the fine print), or Clorox2 at supermarkets. Pure TAED works well, but there's even a better one, read on.
3. If TAED is unavailable, add a quarter cup of 30% Hydrochloric acid (HCL is sold at hardware stores as Muriatic acid) to each one Liter (quarter gallon) of peroxide. HCL may be substituted with one cup of vinegar (a weak Acetic acid) or citric acid (even weaker), but HCL works best due to the formation of Peracetic acid, a very strong bleaching agent (HCL is my favorite method).
Feel free to experiment with various activator to peroxide ratios, and see what works best for you.
Whenever working with corrosive and oxidizing chemicals, always wear rubber gloves and safety glasses for protection!
Contrary to popular belief, basically it's not the UV or the Sun's light what speeds up the bleaching process, rather it's the heat from those sources. So, you can just leave it outside under the Sun, or put a water heater coil set to low/medium into the peroxide mixture, or place the tray into the oven set to low/medium with the door open (important!) for a couple of hours. If you have a cooking thermometer, try to adjust the peroxide mixture at around 70C degrees or 160F (higher could melt the plastic). Stir the mixture often with a plastic or wooden spoon, and check on the color change.
Once it looks satisfactory, wash all the parts thoroughly using a nail brush with soapy detergent like dish-washing liquid and warm water to get rid of all the chemicals, then rinse it several times with clean water. I've done many retro-brighting jobs, and this method works really well.
P.S. There's still one more thing to try, which is using plain and strong Clorox bleach (Sodium Hypochlorite 10%) for a couple of days, since that's a really good bleeching agent too (we shall see ;).
Great video Jeff! I can tell a huge amount of work went into this. So great that we now have a definitive source of real scientific data on this subject that we can point people toward - whether or not they'll listen is a different matter, of course...
Thanks. My hope is that it allows folks to make an informed decision. Some will still prefer the original patina which is fine too.
This is the most comprehensive explanation of and investigation into retrobrite that I've seen. TBH I've been reluctant to try retrobriting in the past, but I have a couple of machines where I'm not entirely happy with the patina and I'd prefer to have them look less yellowed. Many thanks for this video.
Excellent video. Super informative. I appreciate all of the research that went into this -- well done. I have had very good success with full immersion Retrobriting using liquid H2O2 and a 1000W UV grow lamp. I also tested Sunbriting -- it has worked well, too. Great work, Jeff. 👍
That’s the most useful video I’ve seen for months! Thanks for putting in all the work to sort out what retrobriting really does.
Thanks
Holy Cow! AWESOME! Your work has saved me months of research. My pet peeve is when people make claims/assertions without any documentation is a waist of time. Your actual scientific approach: formulate hypothesis, identify possible causes for discrepancies, test - test - and test again, attempt to eliminate possible discrepancies, THEN formulate the outcome. Wow! I just found your channel but I'm a huge fan now. Keep up the good work!
Thanks! Glad it has been of help to you.
I knew Retr0brite was bleaching. I can also confirm that ABS turns yellow in the dark. Last year I did an Alarm System takeover and the old Alarm System's communicator was in a dark attic. That thing was so yellow, the case was fragile it was like poking your finger through a wet sheet of paper. The previous tech left his name and install date in the panel so it was around 11 years. I believe it got like that from the Humidity and Heat. Also ABS in it's "natural" state as in color is anywhere from a off white to a yellow color depending on the chemical mixture before bleaching, dyes and color additives are added.
Yes, heat will also cause yellowing.
I did some research a few years ago about this and found very similar results to yours (but not as thorough)
One of the things that should be elaborated on is the mechanism of the yellow/bleaching of these plastics. The initial yellowing isn't just caused by O2 in the air. It's caused by the natural breakdown process of O2 into an oxygen radicals and ozone (O3). The ozone does it's thing, usually just reacting with itself, but the oxygen radical almost immediately reacts with anything it bumps into. Most of the time it reacts with ozone, reforming O2, but this can also be the CH groups in plastics, turning them into ketone groups, which is one of the ways that plastics yellow (cause afterall, there's more conjugated bonds which act as chromophores). Heat and UV, like you said, increase this breakdown which is why it's inevitable. I know it all too well as a woodworker. The same problems happen there
However, what I suspect, is that these oxygen radicals also act as a way to remove these ketone groups, forming ozone in the process (which is unstable) among other molecules. This process is generally an oxidizing one chemically speaking. Sun bleaching makes sense with this process. But the issue is that you need to start from the oxidized plastic before hand, otherwise you're doing the yellowing reaction mechanism. Hydrogen peroxide provides radicals that do the same thing as O2's breakdown. I think this is where the misguided suggestion of ozone generators came from. Those generators aren't great at making the radicals themselves.
In addition, in my research, I found that someone successfully achieved de-yellowing with other bleaching agents. Chlorine gas is a bleaching agent (but not used as one), and it managed to de-yellow just as well as H2O2. This is despite it not making radicals, but instead it being a very strong oxidizer (the molecule that takes electrons). So a suggestion for future experiments is to try not only other bleaching agents (like household bleach), but even strong oxidizers (within the realm of safety) such as nitric acid and sulfuric acid. It is unlikely that methods using these oxidizers would be any more viable than just H2O2, but it would be more evidence of the true mechanisms of de-yellowing of plastic. Maybe Nile Red or Cody could take a look into something like this
I'm only a few minutes in but I love your explanation of light. It reminds me of how, when learning this in school (about the spectrum) I became hit by a new fact.....I can't see ANYTHING except for light. With the blue truck example you gave, I can't see a truck at all. I can only see light bouncing off an unseen object. The example my teacher gave was a chair and I recall being awestruck at the epiphany that I can't see a chair at all, only light bouncing off the chair. It's both obvious and amazing at the same time.
I had a similar epiphany when I was a teenager when I finally understood capacitive and inductive reactance. It was like a curtain had been pulled up and I saw the obvious for the first time.
Glad I discovered this video. You have cleared up a lot of misconceptions I've had about retrobrighting.
You can straight up destroy fabric with nothing but a bleaching agent. It weakens the fibers of the cloth and if you soak those socks long enough in a concentrated solution they'll just fall apart. No idea if it has a similar effect on plastic but it would be greatly reduced anyway considering the thickness of the substrate.
I can soak a piece of metal in a weak caustic solution and get it very clean. If I use a strong solution I can dissolve the part. Saying the former is a safe process does not imply the later is.
By far the best video I've seen on this topic. Thank you for all your hard work.
Thanks for taking on this huge project and putting it out there.
You say that the plastics you are trying to get back to original are ones that have been stored in the dark.
I have been retrobriting my lego as they parts that have changed colour are ones that have been exposed to sunlight as by being near a window. Some sets I have bought have been burned on one side where they faced or were in a windowsill and the side facing the inside of the room were their original colours.
So I have been using a 3% solution, warm water and outside on a hot day, and the container sealed with cling film to create a hothouse and have been having good results. On a really bright day the greys, whites and yellows can be bought back within a day. At max I would leave in for 36hours. After that there is some colour degradation.
"You say that the plastics you are trying to get back to original are ones that have been stored in the dark."
No, I did not say that. I said that some plastics which have already yellowed may continue to yellow in the dark, even after they have been Retr0Brited. This phenomenon is described in a paper included in the link in the description.
Terrific work, teriffic science, and teriffic fun. Your work is greatly appreciated and reminds us what a treat it is to be alive.
Thank you for taking the time to do this badly needed work. A+ on this paper!
This was such a quality informational video, and your voice is so calming. Thank you so much.
Thanks :)
Great research, Jeff! Thanks for making this video. I'll be passing it around for sure!
Thanks!
Thanks for this. This is what youtube should before. Not just a guy showing the process. But someone learning and explaining for an amazing video.
Historically Potassium Permanganate as a catalyst has been used to accelerate the decomposition of Hydrogen Peroxide. Perhaps a small amount would help with the liquid immersion method. A large amount would probably be counter productive as it would colour the liquid and might affect the plastic being retrobrighted.
Thanks. I have a suspicion there might be some relationship between H2O2 concentration and temperature, i.e. at lower temperatures a 6% concentration of H2O2 is not as 2x as effective as 3% as the temperature of the plastic limits the reaction. Perhaps though a 3% concentration of H2O2 with a catalyst would be as effective as 6% would be if both were at 50C. I don't have the equipment to make that detailed of a study though.
24:30 mark: "..try again if the electrode corrosion issue can be solved." Before Energizer/ Duracell alkaline batteries were in all the stores, they were carbon-Zinc construction, like the Ray-O-Vac "Heavy Duty" with a carbon rod electrode. The biggest of those rods I got came out of the No. 1209 "Lantern" flashlight 6Volt block. Those blocks seem to mostly be inside older camping gear in stores that sell donated items.
Carbon or graphite rods would have worked better. I'm not sure that I'll try it again as it is not really a practical method, it was fun to try though.
@@HeyBirt carbon rods definitely work and solve the murky water and corrosion problems. They are cheap and easy to find also. Works also when doing electrolytic cleaning of metals.
Thank you so much for this amazing video, as a restorer of machines mainly of old plastics and trying many methods or retro briting, most recently I have Hydrogen Peroxide liquid and 2 x 30w UV lamps to help me and the results have been so good so far. Here in the UK we have very limited clear sunny warm days and I’ve found the cling film and crime peroxide to be a bit hit and miss on causing scarring on the plastics. You video informed of of the science and the myths and felt more like a sped up University course and I truly thank you for taking the time and making this video, Thank You from England and thank you for the education aspect. Forever in Debt to you, Dorian.
Thanks for the kind words.
The most scienific version on TH-cam I've seen so far! :) well done
When bleaching keys, note that the bigger ones -- the space bar almost always, but it can be others as well like a Big Ass Enter -- may be made of a different plastic than the rest. Typically ABS is used because it's light and sufficiently stiff for such a large key, while the other keys may be PLA, or POM, or something that's easier to make doubleshots with because they melt hotter. They all start the same color, and may or may not yellow similarly, but this explains the differing levels of bleaching required. I know Cherry, in particular, likes to mix POM for smaller keys with ABS for larger ones. Long before any yellowing happens, the ABS keys have their matte finish eroded away by repeated touching in just a year or two, while the POM keys may take the better part of a decade to get equally smoothed over.
Hi Birt!
If you ever revisit this experiment one way you can quantify the color change with the equipment you have on hand is to load the picture of the item up in gimp or photoshop and check the RGB or CSV values, recording those each time you take a sample.
This is masters degree level of research. Well done. Thank you
Thanks!
Thanks for your work to perform all of these experiments so that we can make some conclusion of how retrobrighting actually works! I am not too knowledgeable on chemistry, but learned a lot and appreciate it.
Hey Birt, I hope you see this comment, as I'm wondering about an aspect of your setup. I'm currently prepping to recreate your 12% H2O2 heat mat setup to do some retrobrighting of my own. I've got a similar setup; same size mat, roughly same size container, the only difference being that I'm using a 30 watt heat mat that has a maximum temperature setting of 45 degrees Celsius. I was wondering how close I could get to the 40 degrees, so I'm testing with tapwater. I've got a polystyrene base with a small sheet of aluminium insulation foil on top to reflect the heat back into the container. The container I've got covered with thick blankets to provide a little bit of insulation as well (not ideal, I know).
I've got the heat mat set to 45 degrees, and put a temperature sensor in the water hooked up to a multimeter. After roughly 12 hours the water only gets up to 30-31 degrees with an ambient temperature of roughly 21 degrees. I double checked and the multimeter is accurate. So, for my question to you: I've gone over your video multiple times, as well as the data you've uploaded to OneDrive, but I cannot find if in your tests, by 'temperature', you're referring to the temperature you've got set on the heat mat, or if you've also got a temperature sensor in the hydrogen peroxide.
Thanks in advance for answering! It's a really great and insightful video, and an awesome contribution to scientific research on this topic.
I was referring to measures temp of the solution. Note that I did not use a full 12% strength other than in testing. I found that 5%-6% worked well but took just a bit longer.
I have a hunch that using string concentrations of hydrogen peroxide might lead to the problem some have had with blotchiness. I have seen this when using caustic chemicals to clean metals. If the cleaning solution is too strong it does not seem to act evenly.
@@HeyBirt Thanks for the quick response! I assumed it was indeed the solution temperature, as that would be the most reliable way of testing. I'll look into increasing the temperature of my test setup, probably by adding more proper insulation to the sides and top of the container.
Thanks for the note on the strength. My conclusions from your data was "Well, if it saves a day and produces the same results, better to go for 12%", but if there is a higher (gut feeling) chance of potential blotches, I think it's indeed better to err on the side of caution and take that additional day for a safer approach.
Bit late to the research results you presented here - this is incredible work! Thank you very much for sharing, I enjoyed every minute of your video!
I came across the retro computing fascination (61 years old, ZX81 was my first computer, the ZX Spectrum really got me into 8-bit "computing" ;) recently; as Speccies are black, there is no reason to bright them - but I found three Atari's 1024 in a storage room of my research group - heavily yellowed.
I am a chemist - and throughout all experiments, research papers, rationals, conclusions, and particular in your case, such nicely conducted experiments, I still struggle with the final molecular interpretation (and I am a bit lost):
"Bleaching" is an oxidation process; in case of alkaline "bleach" ClO- + 2e "->" Cl-, and the electrons stem from what was oxidized. Now, my "problem" ;) is that yellowing apparently comes from an oxidation process as well. Why does an oxidative environment such as H2O2, which is a strong oxidizer, not lead to even more yellowing?
To be honest, I suspect there is something to the effect of radical trapping into "stable" molecules involved? Radical trapping by uptake of electrons and of course chemical rearrangement (otherwise the result would be an anion) is in essence a reduction reaction caused by the radical nature of the agents - not their oxidizing potential. But I may be totally wrong - I am just starting out with all this - and I am speculating on advertising a master’s thesis project on de-yellowing ...
Thanks again, and all the best,
Thorsten
Chemistry is not my strong point but I did my best to understand the information I found and interpret the results of the experiments.
It is interesting that glass will absorb UVB while letting through UVA. The UVA and/or visible light that makes it through a window increases the rate of yellowing. Though yellowing 'can' occur in darkness. Outside the UVB from sunlight has a bleaching effect on plastic.
In either case the sunlight is adding energy, but the resulting chemical reaction is different. UVB is more energetic and as I recall more energetic particles can lead to different results. The use of a bleaching agent like H2O2 results in a reaction similar to UVB exposure and it seem the chemistry of bleaching is well understood. So, this are likely very similar reactions.
But like you I don't understand why bleaching instead of yellowing or vice versa. I never could find a good explanation.
Everything that i've retrobrited turned yellow again at quite an accelerated rate, within 2 years.. and the items were not in any sunny or hot location, and away from direct light sources. I've considered if sealing the surface with an automotive grade matte clear coat with UV inhibitors might reduce the return of yellowing..
Thank you for your dilligence in the literature review and all of your hard work to bust those myths! You did an excellent job of explaining this process in a way that was easy to understand and this information is incredibly valuable :) It's very refreshing to see someone approach this (or any) topic with the good old-fashioned scientific method.
Thank you for your great report!
I am currently bleaching an old HP Laserjet. Part by part. I can make the following interesting observations:
1. the housing of the printer consists of different parts of ABS, which contain different degrees of flame retardants. From no flame retardants to some flame retardants (ABS-FR) to more flame retardants (ABS-FR30)
It can be stated that the higher the flame retardant, the more yellow the parts. Originally all parts had the same colour. The parts without any flame retardant are largely in their original colour. The ABS-FR30 parts are very yellow.
2. at the beginning, the printer stood for 10 years in a room where it was exposed to sunlight on one side through a closed window. These parts facing the sun are more yellowed.
3. the printer was then left in a room without any sunlight for 10 years. Nevertheless, the yellowing has progressed, some parts that still looked good after the first 10 years were heavily yellowed after another 10 years in the dark.
I think you have to consider UV radiation depending on its intensity. In low doses, it increases chemical processes such as yellowing. In this case, it acts as an amplifier of chemical processes. In high doses, on the other hand, it has a bleaching effect and counteracts yellowing.
There are also reports that unopened cases in their original packaging (sealed airtight) did not yellow in the cellar, whereas the same product in opened packaging in the same cellar is heavily yellowed without sunlight. So oxygen does indeed play a role.
Obviously, oxygen and UV radiation have a yellowing effect in low doses and a bleaching effect in high doses.
I suspect that every bit of plastic in consumer items has some degree of flame retardant added. As noted by the NES, different batches of plastic yellow differently.
The band of the UV is what determines the bleaching vs. no bleaching effect.
Hey, something I'm having trouble understanding, after watching the video (and I'm hoping you can explain) is: it sounds like heat and UV speed up the yellowing process caused by oxygen... But also the UV from the sun can be used to bleach? So the sun both yellows and bleaches? How do you know which one will happen. If I leave my C64 on a desk facing the window will it get more bleached or more yellowed?
Cool, thanks for these worthwhile efforts, Birt!
I particularly like that you noted the potential limitations of experiments (e.g., that you didn't control/measure the room light). Always good to explicitly mention things people might want to control for when trying to repeat.
I also liked your rationale for using just (low)heat indoors to control for uneven results. I think I'll use this method if ever I decide to try.
Thanks. I may have to been able to borrow some fancier lab equipment from work but I want to use an approach that others can replicate and build on.
What a great, in-depth exploration of the various approaches (including some novel ones). Living in the Sacramento valley, our summers are very hot and very dry. Humidity is ~30% for about 6 months straight typically. The drought has made it worse. I leverage this, and most work-from-home opportunities, to sun-soak some of my Amiga collection previously brightened (when they need a booster). It seems to keep them in a healthy aesthetic.
One thing I've started doing the last year is focused on key caps. Instead of removing them, I'll brush on a 1:2 ratio of liquid oxiclean/water in situ. The amount is light and the hot. dry air minimizes corrosion opportunities. I'll mist, or brush on fresh water periodically (~every 30min) and, as long as I am patient, I can coax the keys back to youth. With brown keys, like the breadbin, I'll carefully apply the oxi solution with a paint brush to the concave area of each key-again, refreshing with vaporized water periodically. This often leaves no perceivable impact to the key's brown color as long as I am vigilant about treating it and the sun is co-operating. Unfortunately, the smoke from the last month or so has limited options on whitening.
Thanks again for the great video and interesting research, Jeff.
Thanks for the feedback on the brown keys. It sounds like there is something to using a more dilute solution and being patient rather than a stronger solution.
Very informative. Thank you so much, for taking the time to make this video :)
Hi Jeff. I'm curious if vapor would work also. This, if it works, would reduce the amount of HP to be used.
For example a big pan with a lid put on the (induction) stove on the lowest setting.
Suspending the knob above the liquid, so the knob isn't submerged in the HP, except for some drops formed on a horizontal surface of the knob. The heat would make the HP evaporate. What are your thoughts ? Thanks for the video.
Some people are using vapor successfully. You need to have the whole system enclosure, so the vapor condenses evenly.
Excellent video. Changed my mind on a lot of things.
Water treatment engineer here! Retrobrite is just an advanced oxidation process. In these types of processes, you want to create hydroxyl radicals, which are tremendously potent oxidants. You can achieve this by combining hydrogen peroxide with UV light, as well as with ozone, titanium oxide, and iron in acid medium. This technology is awesome for destroying recalcitrant organic contaminants.
Yes, that was my thesis, Retr0Brite is an oxidation (bleaching) process. Somewhat anticlimactic given many of the myths that has grown up around it but that is what it is and it works.
Hey Brit! I'm curious if you've done any experimenting with the "vapor" method of retr0briting which is gaining popularity. This is similar to the immersion method, but involves placing a small amount of high concentration hydrogen peroxide in a sealed container and exposing it to heat (usually the sun) to induce evaporation. The parts are not submerged or otherwise directly exposed to the hydrogen peroxide itself, only the resulting vapor. Claims are that this uses much less peroxide and results in more even exposure, though may be a bit slower than other methods.
I know of it and have a friend who uses this method almost exclusively, so I know it does work well. The need for sunlight is the only downside.
I thought of a hybrid system of a small pool of H2O2 in the bottom of a container and small submissible pump to mist the liquid to cover what is being treated. If the pool of liquid is heated, as I did with seedling mats in this video, you should still have the warm environment and need much less H2O2. I even bought a pump for this but have not built it yet.
I recommend for small and medium size things to use a vacuum sealer that does liquids, pour the peroxide in a vacum seal bag over to the top of the item and vacuum seal carefully in the sink. Then just use a sous vide heater to heat regular water with the vacuum sealed bag inside. This will conserve peroxide and heat evenly without exposing the heater to the peroxide.
Thank you so much for your time and feedback to community !
radicals are not ions, and not necessarily charged. Radicals are atoms or groups of them with unpaired electrons.
Thank you for the clarification.
I thought this was the best video covering the actual science and facts regarding rejuvinating our precious computers... Top notch science, Birt.
Thanks for your great video, Britt! You don't know how many people swear to me that Retrobrite "fumes" causes cancer, that is the primary cause of brittleness, that is dangerous chemicals, etc. Love your scientific approach, did my own animation on my channel a few years ago but your extensive research blows mine away. I have retobrited more than i can remember. Thanks again and let's keep having fun learning new things!
First time I have heard the cancer myth :)
The color of the carrotine molecule shown is not due to its shape but instead it's conjugated pi bond system. The center section consisying of a line of double bonded carbon atoms is special. Thrre are two kindsbof bonds, sigma bonds and pi bonds. The sigma bonds are localized between the carbon atoms. The second bond, the pi bond, is not. The electrons takig part in the pi bonds can move throughout the entire conjugated pi system. This is a common theme in organic dyes. Six membered aromatic rings can also take part in these conjugated systems. Many organic systems owe thtir golor to these sorts of conjugated bonds.
Inorganic compounds typically owe their color to ansorbtion of light by the outer electrons. Examples of these are colored forks of oxidized metal ins in solution. Som compubds have distinctive colors in their unoxidized states as well. For example gold and copper. Bromine and iodine also have distinctive colors in their ground state. Iodine is purple and bromine is a redish brown. Unlike metal atoms, which oxidize to a positivly charged state by losing an electron, bromine will reduce to a negativly charged state or can take part in covalent bonding. In the absense of other factors, solutions if negativly chatged bromine ions, or compounds containig covalently bonded bromine are colorless. However, bromine solutions are well known to turn yellow over time. This is caused by the bronine losing an electron, and going from its Br-1 reduced form to the +0 form which consists of 2 Br+0 species covalently bonded. This is accelerated by exposure to oxygen and light.
Another reaction that is common is that a photon of light os absorbed by the carbon halogen bond in an organohalide. The halogen is removed and grabs the hydrogen from tfe neighboring carbon, leaving a double bond. This is the opposite of such an acid adding across a double bond and creating an organohalide. Depending on the encotonment, hydrobromic acid can also further go on to create molecular bromine (consisting of 2 bromine atoms covalently bonded).
The double bonds which can take part in conjugated pi bond systems should neighboring atoms also have such bonds can easily create absorbtion bands in the plastic that could cause yellowing.
Its also possible that residual Br2 could build up and cause yellowing.
Hydrogen peroxide and light creates free radical spevies that are highly reactive. They are commonly used to intiate various reactions. For example, peroxides or light, or both are commonly used to intiate polymerization rezctions. They are also used to intitate ractions of halogens like bromine. Free radical reactions involving peroxide, light and halogens are commonly used to add halogens to species with double bonds. Doing so to one that takes part in a conjugated pi system would alter its absorbtion of light.
So bromine taking part in both the yellowing and bleaching of plastics is not at all implausible. There are other reactions that free radicals can cause as well that might remove and create yellowing as well. The fact (as is well known) that plastics sitting in sunlight yellow much faster than NOS plastics sitting in a box, but even plastics stored in a dark place yellow, and that its also accelerated by ozone, suggests that oxygen AND light are involved. Bromine plausibly yellows plastics over time by multiple mechanisms. But just because non-brominated plastics also yellow does not suggest thd bromine plays no role. Different plastics may yellow or whiten by slightly different, or vastly different mechanisms. Its also the case that some substrates are resitant to yellowing, and others do not brighten with peroxode and light.
Thank you very much for the video. I have wondered about the yellowing of plastics for years. I found this video through a support group for TRS Model 100 computers. I am a 71 year old retired Mechanical Engineer. My Counselor says I am a Researcher. Since a good Mechanical Engineer can do anything, and I am a Researcher, I was able to follow everything in your fantastic and extremely informative video. There are so many great takeaways. Question: How long did it take to make this videlo?
What doesn't make sense is that I had stuff in storage for nearly 10 years in complete darkness and cold temperatures, and my SNES, the SNES mouse and a Ghostbusters car all turned yellow.
Temperature and light only add energy to the chemical reaction and cause it to happen faster. It will still take place in the dark.
What a wonderful, in-depth video. After looking around at all the myth regarding retrobrighting I couldn't get a handle on how it was supposed to be working. Your video and research has made the process very clear. Thanks for all your effort and true scientific analysis. Now all I have to decide is, do I really want my yellowed plastics white again?
I loved this video, Jeff. I'm curious if the 7% H2O2 I see on Amazon for water systems would work the same as the 6% solution. It doesn't have any other ingredients beyond the peroxide and water, so I don't see why there would be an issue but I would like your thoughts on it.
I don't see why it would not work. Compare the price to getting the 12% from a local beauty supply store. Around here that is the least expensive option.
5:40 Very good analogy! Cooking and chemistry aren’t that different. Alloys of metals are the same way; a few small ingredients change everything.
I think that it has been demonstrated that heat without light is a good enough 'energy source' for the Hydrogen Peroxide to do its thing. UV light is not necessarily required. A case brushed with Peroxide Cream in a zip lock bag in an oven at 50 degrees that is brushed periodically (approximately every 20 minutes), with the reapplication of cream as required to stop it drying out or crystallising, has been demonstrated to work well. Any thoughts on this?
Light and heat both add energy to the chemical reaction so either will work. The problem with using UV light and the cream is the potential for a streaked result.
Most household ovens do a very poor job at temperature regulation, so it is advisable to measure the actual temp in the oven with a precise thermocouple. You might find you the bottom of the part near the heating element gets much hotter than the top or side. The advantage of using immersion in dilute H2O2 is that the temperature is consistent.
Check out the video I did a few months ago on a VIC-20 that was the color of cheddar cheese. For fun I left it in the Retr0Brite bath for 7 days.
there is a question seems nobody yet answered. What is the change in the plastic strength, both from yellowing, and later on retrobrighting. do we get back the strength before yellowing, or do we worsen it altogether? I can think of trying it using printed ABS with rapid yellowing thru heat and oxidation to compare with a part that has been vacuum sealed and another part that has also been yellowed but retrobrighted later on.
Both the yellowing and Retr0Brite process are going to have a minute negative effect on the strength of the plastic. Only in extreme cases of yellowing will the integrity of the plastic be compromised. The Retr0Brite process will not restore any lost material or strength to the case.
Since there are so many variables, i.e. the exact mix of plastic, the amount/length of UV exposure, exposure to high heat, etc. it is impossible to generalize as to length of exposure vs. amount of damage. That would only be valid on one type/mix of plastic.
The plastic mix for 3D printing is not the same as used for injection molding. They are designed for two different processes so it would be hard to compare UV effects on one to the other.
@@HeyBirt well that's the thing. In simplified terms, let's say yellowing makes compound A become compound B, and from evidence it seems that the higher the concentration of B in the plastic, it appears to be more brittle. However we don't currently know if any of the bleaching processes are making compound B become compound A again (a possibility), therefore returning the strength to the material, or making B become C, and in this later case, if compound C is more, or less, strong, than the original compound A.
Obviously 3D printable ABS is not the exact formulation as injection molded ABS, yet it is similar enough to serve as a starting experimentation point, as the differences would not be so drastic as say, comparing ABS with PETG or PLA or any other plastic. Indeed as you said yourself, every manufactured ABS is different, so by testing with printable ABS we're most probably in the same amount of difference than using any ABS, as the formulation is never going to be what Apple, Commodore, or Nintendo used 30 years ago.
Don't get me wrong I think you've done an amazing work with your video, I'm just thinking on what the next steps could be without, as you said, the "expensive" (and let's not forget, difficult to get) equipment a proper lab would have (that could even formulate more precise ABS variants). That's why I suggested 3D printing as a doable next step.
@@TinkeringDaemon The problem is that not even all ABS is the same. It would be near impossible to make a generalization about what effect a certain exposure has on ABS brand A will have on any other brand.
There are many, many papers written about photodegradation where they go into detail about the various plastic mixes (different formulations of same plastic type or different plastic types) they use and how they were exposed. You can infer some general characteristics from these tests, i.e. UV exposure is harmful, but you can't conclude that since Plastic A performed a certain way that Plastic B will do the same.
This is one of the reason that there are standards that products are tested against. That is the only way you know a material meets certain properties, such as resistance to UV damage. These sorts of tests are well beyond a home workshop though.
Thanks for this very informative video, debunking the bromine nonsense and showing what retr0briting does to the plastic.
In the LEGO community the yellowing of white and grey ABS pieces due to UV light is considered a pretty big problem without a permanent fix and many report that even sets kept in a dark basement undergone yellowing.
I have tried the 12% hydrogen peroxide + UV light activator method many times but sadly the "bleaching" is only superficial and temporary and after a few month the parts will be yellowed again even if kept in the dark. What I did not test is storing the treated parts in an airtight container + refrigerator and check if the oxidation is slowed.
I also noticed on my white NZXT Phantom computer case, that the rear top area where the most heat gets accumulated caused very strong yellowing so UV light is not even needed to cause damage.
Wish there was a permanent solution to reverse the yellowing because my expensive LEGO Star Wars sets look horrible and are now pretty worthless.
If I wanted to try the immersion with heat method but I already bought the 40V cream at Sally’s…could I just put the cream in the water and stir it around in it so it dissolves?
You can dissolve the cream in water, I have done that in the past. It does not store as well after you are done though. With the liquid I can filter it and store it in a large plastic jug for months to use again. It does loose it potency over time though.
Thanks, a bit too much for now, so it is in Save for later for a re-watch. I have to say I go for sunbrite nowadays, as it is very easy to do, and almost as succesful as previous messing with chemicals.
My hypothesis: Epoxidation followed by Hydrolisis. Water acting as an acid here. It "changes" the conjugated system of the chromophore. "more double bonds => more absorption => colorshift to yellow", a bit simplified...
I suggest you use Sodium sulfate as an electrolyte. Should be safe.
That's all i can add, it's been years since Uni or working in the field of chemistry.
Nice work, thanks!
What doesn't make sense to me: If the process that causes the yellowing is oxidation and the process by which the bleach works is also oxidation and if that bleaching process is what works on the plastic parts, then we are not reversing the yellowing process. We are oxidizing already oxidized material. Oxidation isn't like subtraction, where to negatives make a positive. The reverse process of oxidazation is reduction. So: what is indeed happening?
...Not only should the oxidation by the bleach not reverse the oxidation that caused the yellowing, it should also MAKE more yellowed material, as we stated earlier, that oxidation is what leads to the yellowing. So: one of the processes needs to involve reduction or what is happening is not a reversal but a further transformation and probably destruction of the oxidized material. Something is not adding up. Can anybody help cleat up this contradiction?
What's with that asymmetric colour wheel at around 3:30? Why the size difference between some of the pie pieces? The colours are odd too. From orange to orange-yellow to orange to red - why?
It is just a convenient graphic that I grabbed. There is no significance to its oddities.
@@HeyBirt It's conveniently wrong. :D
@@ropersonline But it served its purpose of showing a lot of different colors, that is all it was used for. The next slide shows a proper spectrum which also relates color to wavelength...
Such a relief that you didn't come out with anything that went against what had already been shown to probably be true! Now we can actually know these things are true rather than just suspect it. Someone had told me about using an auto stirring heated flask setup along with hydrogen peroxide and TAED a couple of years ago and said how effective and controlled it was and this is the first time I've heard it being talked about since.
The goal was to find out how it worked so everyone could make an informed choice about it. Hopefully is helps to dispel some of the myths as well.
@@HeyBirt The only thing I think you didn't touch on was Neil's sous vide method, which stirs the water as well as heating it to a preset temperature. That may be better than those pads - although the stick is more expensive to start with. Again though thanks!
It is accomplishing the same thing, a consistent heating of the liquid. Neil sealed the parts in bags of H2O2 to avoid forcing the sous vide from having to pump it.
The sous vide machine pumping the water is a side effect of how it works, i.e. pull the water through to heat it and distribute it. The heat mats heat the entire under surface of the container so not as much to be accomplished w.r.t. heat distribution.
Agitating the liquid H202 might help speed up the reaction though by ensuring a more homogeneous solution throughout.
When I go to add a comment and find that someone else has already written it for me. Then I look at the composer to find it’s someone I’ve already got a deep respect for.
So all that’s left is to thank Hey Birt! For such a great and insightful video.
The heated mats are a great idea, I’ve been using a brewing immersion heater (purely because it was something I had to hand) which can only get to about 34c.
@@HeyBirt Yes. That means the 3 most successful/reliable ways to do it in my subjective opinion are your heat pads, Neil's sous vide and Kai's heating mantle. And they're all essentially the same method at heart.
Now I wonder if there is any scientifically explained approach to restore black plastic. Among all the black console restoration videos on TH-cam there seems to be no solution aside massaging all kinds of greases into the surface or a heat gun treatment to make them look new. But do one of these actually work and if yes how?
I guess it depends on how the plastic has been damaged. The sun will have a bleaching effect on the black pigment, there is no way to prevent that.
Various topical treatments, the 'greases' as you call them, help to improve the appearance and many will help protect from further UV damage. I like to use 303 Aerospace protectant for this purpose.
The heat gun trick is an old one and just remelts the outer layer of plastic. You also stand a very good chance of warping and burning the plastic using this method.
So if Retr0bright is essentially a bleaching process, should we be using it on plastics that are intended to be colors other than bright white? Or, what are the best practices we should be following when working with colored plastics? I'm thinking largely of things like SNES cartridges, which have a medium grayish-blue for their original color. I also have a Famicom cartridge that was originally bright blue, but has turned a lovely green along some surfaces.
We are all used to the Chlorine bleach used in our laundry having an adverse affect on colored cloths. This is more of an issue with the dye used. I add a little Chlorine bleach when washing my white cloths and it does not harm my white tube socks with colored stripes.
The Retr0Brite bleaching process is not really turning something white per say, it is turning it less yellow, i.e. breaking the double atomic bonds shifts the reflected light away from yellow and back to closer to what the original color.
Some colored plastic does seem to have problems, from what I have seen this mainly seems to be with the brown plastic over white plastic key caps. When trying to Retr0Brite the white plastic lettering sometimes the brown will splotch. It is hard to know if this will happen until you try. This might be a case where sun bleaching is a better option.
Those 20W heat mats only [barely] raise the liquid 20F over whatever the ambient air temperature is. (Remember, these are intended for supporting seed germination.) If it were room temperature inside, the highest temperature the liquid would be -- with the heat mat on its highest setting -- is ~90F. Are you sure this is enough for retrobright? It seems to be that the pieces would need to be submerged for a matter of several days. I feel as though the best thing to do (at least, in a warmer climate) is to put the container outdoors and in the shade, while having the heat mat underneath as a supplemental heat source. It would be ideal if the outdoor temperature is 85F+ in the shade.
You will notice I insulated around the container which was enough to raise the liquid temp to 38C to 40C. I also compared the difference in time at various temps/concentrations of H202. The point of the heat mats is it lets you Retr0Brite anytime, any season, in a controlled manner.
@@HeyBirt Hey Birt, thank you for pointing that out; it seems I had looked over the section wherein you talked about insulating the container with cardboard and foam panels. I would be interested in trying the same, as I'm working with an indoor ambient air temperature that isn't particularly warm. Granted, to eliminate as many steps as possible, a stronger yet similarly controllable heat source would be nice to have. I've seen at least one person have success by using a sous vide for retrobright, so I may look into that and determine whether or not it can sustain a reasonable temperature within a large container that has no additional insulation.
@@icantgivecredit871 It is very important to be able to precisely control the temperature. If you get the liquid too hot the plastic parts can warp, even well before you reach the glass transition temperature. I suggest aiming for no more then 50C. I chose 40C to be well on the safe end of things.
There is no reason not to insulate the container. Even a simple cardboard box over the top of it works wonders.
@@HeyBirt Okay, I'll ensure it doesn't go any higher than what you specified. I'll likely buy both the seedling mat and the sous vide, so I can gather findings on each. The sous vide is more expensive, but it should cut the treatment time considerably. (The sous vide has a precise thermostat as well.)
Soo, ive seen people use UV lighting, mixed with HP and heat. Another vid says the UV light isnt needed and doesnt make sense, since it was UV light that damaged it in the first place, and it only causes it to yellow again in a few days. So are you saying the UV light doesnt cause it to yellow again soon after, and that no matter what, unless you spray protection on it, anything can yellow again in a few days?
Did you watch the video? I explained all of this in great detail.
I came here looking for a more scientific approach, and I am very impressed and thankful for the time you spent on this. It's also clear now that the different techniques may be selected as much based upon the part being bleached as it is about the speed of the results. Thinking of my collection, I can see that some techniques may be needed for different components. My IBM PC340GL case has a metal shield permanently attached to it which is not going to do well submerged in peroxide, the creme/film technique risks the "marble" effect, so maybe that's just a "sunbrite" with regular rotation and just accept it will take more time. The drive bay covers and front plastics can sit in peroxide on a seed mat indoors and do just fine.
Note: I learned about the damage peroxide does to metal when I tried to 'weigh down' a case with multiple big washers screwed lightly into the case standoff - trying to prevent the accumulation of bubbles from causing the parts to float. The washers 'rusted' and I had to clean the new rust stains off the plastic...
I have found that aluminum, brass and copper do not seem to be affected by H2O2 at all. If steel is chrome plated it hold up well, common zinc plated steel fasteners will rust.
Thank you so much for this thorough research project, I'm looking to retrobright some of my own electronics, and this video provided a lot of great info and a fantastic method for me.
Very good work! Lots of good info, and very good explanations on the processes
Hey Birt, putting this to the test. I just put out a table full of Keyboards and Amiga case parts that are badly yellowed. I will give them a few days and report back. I LOVE the idea of a way to de-yellow plastics without any environmental impact whatsoever!
I have had a GBA glacier color shell in a 3% hydrogen peroxide bath and sealed UV light box for half a month with no noticeable change to the yellowing. Anyone have any idea why? I was hoping this video gave more insight but am still confused.
As shown in my test results a 3% solution is very slow acting. Hydrogen peroxide breaks down with time and the process is sped up with exposure to light (which is one reason why light helps speed up the process and why H2O2 bottles are brown). If your 3% solution was old, it may have already been partially decomposed.
There is a great difference in the quality of the various UV 'grow' lights sold today. I would not be surprised to find that one claiming to be a UV source really is not. The water itself will block some of the UV.
As I mentioned in the video, I think the heat mats are the way to go. It is a very controllable process.
Is there an explaination as to why the bleaching of ABS plastics does not work with Sodium Hypochlorite but does work with Hydrogen Peroxide?
Bleaching agents (chemicals) do not all react the same with all materials. Industrially you will find that different bleaching agents are used for paper than clothing, etc.
Excellent work mate. This video was enough for me to decide retrobriting my SNES. Cheers, mate.
Glad it was helpful. I was sort of in the same boat, wanted to know how it worked rather than believe the myths.
Would a heating element like a sous code work as well?
yes, but I'm not sure how the suos vide would hold up to the H2O2. Perhaps placing your plastic and H202 solution in large plastic bags then put the bags in a tank of water with the suos vide?
Great video, how long did the heated water method take you? Will it take any text or colors that are supposed to be on the plastic your treating (in my case knobs with colored caps) off in that method?
The amount of time depends on the plastic, amount of yellowing, concentration of H2O2 and temperature. With a 6% concentration at 40C it took about 2 days.
Sometime with dark keycaps with lighter lettering (two shot injected, i.e. the letting is white plastic the key body brown plastic) the dark plastic might blotch. This depends on the exact plastic used.
@@HeyBirt thanks for the response! I’m wondering if the cream and UV might work better for my knobs... I’d like them to go back to original Grey and ideally not loose any of the color on the knob caps... and ideally, within a 4-8 hour time frame.
@@HeyBirt the plastic isn’t drastically yellowed, but certainly noticeable. I believe it’s painted acrylic.. when you say concentration of H202, are you referring to the ratio of water to the Salon Care 40 (clear), or do you use the SC 20 or 30? Thanks for you help.
@@Musinformation96 Using cream and UV won't keep them from splotching if they are prone to that. You might try sunbriting them instead.
@@Musinformation96 If it is paint then H202 will not do anything.
If you have SC40 that is 12% H202. So if you mix 1L of SC40 and 1L of distilled water you will have a 6% solution.
Excellent video! I was wondering if you had any information on the unusual non-yellowing plastic that was used in IBM PS/2 computers (at least in the early models). I have a 32 year old IBM model M PS/2 keyboard that looks the same as the day I got it as my 16th birthday present (sadly the old 286 system it came with is long gone - I kept the keyboard because I loved its typing feel). Every other classic "various shades of beige" computer component I own has yellowed but the old IBM keyboard seems utterly impervious to yellowing or showing signs of age. That thing is the Dorian Grey of my computer collection. Was there something special in the formulation of the plastic IBM used and if yes, why did this not become common (cost? toxicity?).
The very early VIC-20s are the same way. I can only guess that the pigment used was more effective at blocking UV damage.
IBM often painted their enclosures, so you're not looking at plastic. You're looking at paint. :-)
@@nickwallette6201 It's a keyboard and no, it's not got a weird coat of paint on it. It's just molded plastic with a lot of metal internals. Old Model M's were designed to imitate the feel of typing on an IBM Selectric typewriter. The thing is incredibly heavy and durable. The plastic used in them is known to not yellow (or if it does yellow, the process is incredibly slow or delayed by many decades).
I have seen it discussed in other videos and have visible evidence sitting on my basement shelf. My other "antique" mechanical keyboard is a 21 year old Keytronic model that started roughly the same tint as the IBM and has been stored with it for a few decades... only the Keytronic is almost banana coloured now but the IBM just doesn't change. It's something about the plastic composition IBM adopted for that line. It had some downside which caused it not to be broadly adopted and later dropped by IBM.
A bit of digging suggests that IBM used a different types of plastic from the common type (PBT and possibly something else instead of ABS) and most users report little to no yellowing to this day on IBM plastics from that era. If the sources I found are correct, they don't have a fire retardant agent in them that tends to accelerate the yellowing process in addition to being different plastics. Presumably they will eventually yellow but they just seem to be doing it very slowly in most cases.
Yep, I have a Model M. And two Model Fs. And a whole pile of PC/XT/ATs, PS/2s, a PS/1, a PCJr, some RGB monitors...etc...
I don't have my Model M out right now, so I'm not 100% sure. But, a lot of that other plastic is painted. I made the mistake of taking a Magic Eraser to my 5151 display enclosure and got right down to the bare plastic -- which, FYI, is not beige... in case anyone's wondering. :-)
Great video. Thorough explanation and love the scientific approach. Thank you so much!
Would you recommend another heat mat? The one in the link is unavailable. I’m not Amazon savvy, the options are overwhelming! Thx
I noticed a few days ago that all of my older Amazon links quit working. I'll fix them and post again when they work.
Just fixed the link.
Very interesting! I was looking forward to a scientific explanation for the effect of hydrogen peroxide for a long time now. Retrobrighting is great but the next step would be to figure out how to protect the ABS plastics from the oxygen corrosion. I wonder if a clear anti-corrosion spray would work well on plastics as it does on metals. Together with UV protection that would shield the plastic from harm and stop (re-)yellowing.
A product like 303 will help as it has a UV protectant and it coats the surface limiting exposure to the air. You could spray a clear coat on but that might alter the texture, etc.
Moi sur mes voitures tableau de bord j'utilise un produit depuis 20 ans de chez vous (usa) megulars natural plastique et ça fonctionne
How can oxidation both cause yellowing and brightening? It doesn't make sense. Plastics on electronics spend most of their time in-doors where there is a substantial lack of UV-light. What there is more of, is heat, and other gases. Plus reduced ventilation. On the other hand, I've seen people brighten plastic with just heat.
My theory is that yellowing of plastic is caused by "low" oxidation over time. If that's the case, storing your plastics in-doors, and especially inside containers, will cause yellowing over time, and that a UV protectant might actually contribute. When putting yellowed plastic in an environment where oxidation is not just "normal", but "high", you compensate for the long period of "low" oxidation, but some damage might already have occurred. Oxidation is increased with light and/or heat and/or chemicals. The cheapest, simplest option seems to be to place the plastic outdoors on a not-too-hot sunny day while ensuring even coverage. Have I tried it? No.
Sunlight has three 'bands' of UV cleverly named UVA, UVB, UVC with UVA being the longest wavelength and least energetic, obnoxious and dangerous.
Earths atmosphere filters out UVC which is great for us. Regular window glass filters out UVB, you get get a sunburn indoors. About 75% of UVA still gets though and causes the yellowing to occur. Fancy modern windows might have UVA blocking film applied to the glass as well.
When you are whitening the oxidation process is working on the yellow chromophores. This is true is you are using hydrogen peroxide or the sun. When plastic is outside and exposed to UVB it gets bleached.
Have you considered humidity as a factor? It seems like in many cases, when these electronics are kept in humid basemants, the yellowing is more pronounced.
I have not seen anything to suggest that higher humidity levels increase the rate of yellowing. New plastic that has been kept in a dark cool place can still yellow. Exposure to higher temperatures and/or UV increase the rate of yellowing.
What a thorough, exacting treatment of the subject. Thank you for your exhaustive work. I'm looking to try this out myself, following your preference of 12% liquid hydrogen peroxide submersion and a heat pad only. Do you have any guidance on about how long the initial submersion should be for? If you said that in the video already, I apologize for missing it. Thank you
There is not set time for treatment. Check periodically and take out when it looks OK to you. The more yellow the plastic is the longer it will take. Also keep in mind that it seems to work faster at first, i.e. it will take longer to get that last little bit of yellow out. Having something to use as a comparison for the color change is helpful.
@@HeyBirt That's great advice, thank you so much
As somebody who went through a punk phase in college, it seems completely obvious that hair bleach, when applied to yellowed plastic, bleaches the plastic.
I do think it probably does damage the surface layer of that plastic, rather than returning it to its original state, but it's probably a very thin layer (the same few microns that have yellowed). It might speed up the rate of wear from typing, but it's probably insignificant compared to just using the keyboard another year. And if it is for a museum or collector's piece, the aesthetics are probably worth it.
Yes, the Retr0Brite process does indeed have some very minute effect on the surface layer of the plastic. But as you point out so does using the computer, or wiping it with a cloth, handling it, etc.
Great video! Thanks for the hard work!
Great! This answered a lot of my questions about this new (for me) technique!
Sir, can we use a Aquarium Water Heater?
If the H2O2 does not corrode the heater it should work OK. I'm not sure if such a heater can be set as high as 40C~50C.
Yes, it is bleaching. If you go too far/long, it will become lighter than original. I have over-bleached keyboard keys by leaving them in heated peroxide for too long.
Good point, all things in moderation. The plastic used for the key caps seems to react a bit different is many regards. One of the benefits of 'slow cooking' using the heat mats is it is harder to over cook something.
I guess it could be like bleaching clothing. Some colors are not affected by a small amount of bleach and some wind up with bleach splotches.
@@HutchCA I suspect it is sufficient to change only the surface to a few microns to change the perceived colour. One could experiment by "over retrobrite-ing" a piece of plastic and then slicing it to see if the colour change penetrates, or try it with a yellowed piece of translucent plastic and see if it can be made totally clear again.
I tried retrobrighting twice - one success, one blotchy mess. The interesting thing is I was using the "wrong" chemical. I used Draino/Sodium Hydroxide. That's another case for the bleaching theory.
The lye will clean it for sure but will also probably damage the plastic as you found out. Sodium Hydroxide does work wonders for high resistance conductive rubber key contacts though. I have another video on how to revive them.
I would encourage anyone to go ahead with retrobriting. Sure, it's possible it might not look good when you're done, but IMO, it doesn't look good when you start either. So, what do you have to lose?
The vast majority of my stuff has turned out anywhere from "well, that's _better_ I guess" to "perfect!" with very limited negative outcomes. Namely:
* A couple CD bezels that lost too much intended yellow and started taking on a reddish-gray hue (Creative [Philips OEM] CD bezels.)
* A front plastic bezel on a desktop PC case that took _FOREVER_ and didn't completely bleach all the yellow, but also whitened too much, and is now a splotchy albino beige. (I overcooked this one -- further proof of the bleaching process? -- and it also spent a lot of time floating up to the surface, i.e., not submerged.)
* Some screen printing loses some of its saturation (Creative and Plextor CD bezels, mainly), but this is fairly rare. Most screen printing is perfectly fine.
* Anything painted has a chance of becoming un-painted. Happened to a case badge with a painted background (totally dissolved the paint and is now bare metallic), and the inside of a transparent plastic sticker on the MHz display / button legends of a mini tower case (some spots of lost color.)
To avoid:
Anything painted should be removed, if possible. Don't carry on too long -- if it doesn't work within a reasonable amount of time (relative to your process and other results), then call it quits and take what you can get. I personally prefer submersion in liquid (store-bought 99c antiseptic Hydrogen Peroxide bottles, because it's easy to get hold of -- provided you're not in the middle of a pandemic), and use a couple 30W UV LED panels, but if heat works as well, that's probably better.
So, to sum up, in the worst case, it doesn't turn out well and you will need to paint it. How's that any worse than looking like a smoker's lung? :-)
Great video Jeff, thanks for putting all that effort into it.
Going to 70C for the bleaching process should not be any problem, as ABS is a thermoplastic and stable to above 100C before any softening occurs. So using hot water and UV light together with hydrogen peroxide should be ideal then? Did you test all that together to see how the combined effect worked?
The 'glass transition temperature' of ABS is about 100C but you have to consider what that term means. It is the midway point between the solid glass state and rubbery state, by the time to reach that point the material is already quite reduced in strength.
We also don't know exactly what is in the plastics we are dealing with, as pointed out a high impact ABS will have a lower glass transition temperature around 85C and a maximum service temperature of 65C, i.e. above 65C it should not be used continuously as it is already weaker. This latter term gives us an idea of how reduced in strength the part is well before the glass transition temperature.
You also have the issue of large items like a space bar distorting as they heat unevenly. Also as mentioned the surface temperature of your container may be well above the liquid temperature.
Also consider that above 50C is considered a 'scaling temperature' and should be approached with due consideration for safety.
@@HeyBirt Absolutely, but a key in a tub is not in use, or really put under any stress.. So according to above you can go to 65C no problem. And if you cover the outside of the vessel in aluminium foil you basically have an all round mirror, the uneveness in the foil add to the light dispersion also which pretty much removes any chance of uneven light. Any remaining factors are pretty much those that you learn in science as "minimal impact" and round off to 0. :D
ABS is easy peasy to restore.. Try 50 year old computer cases with a foam sandwich construction that litterally breaks on touch.....
@@MrZnarffy It's put under the stress of its own dimensional stability, and gravity. I would suggest not relying on intuition, which is often based on circumstantial evidence that may or may not be relevant. Take something representative, but not valuable, and give it a try.
Many people use hair dryers to soften old plastic to prevent breaking pieces that have become brittle with age and natural loss of plasticizers. What do you think the temperature is coming out of a hair dryer held six inches away from a surface? If, at that point, the plastic is already becoming malleable, consider how it would fare at that temperature for a prolonger period (hours, or a day or two) while treating it.
@@nickwallette6201 Not talking hair dryers.. I got experience working with ABS, since I'm a biker who likes speed, and bike fairings easily cost $1000 per piece. And 3d print in ABS as well. You know you can dissolve ABS in acetone for example, and when the acetone evaporates, you have solid ABS?
The stuff I have issues with is 50+ years old sandwich constructions of some kind of styrene foam and abs... me and my mates call that "fragilium"....
@@MrZnarffy I don't quite understand what point you're trying to make. The point I am making is that it seems you can soften ABS considerably by using a hair dryer. It's difficult to say what temperature, exactly, that air will be (since it's not often regulated - or at least not user-controllable), but from what I can tell, a hair dryer's average air temperature is more like 55-65C. That suggests that it's going to be solid, but malleable, at far less than 100C, with the potential to change shape under normal atmospheric forces.
I don't know what acetone has to do with this, since that's a chemical reaction, not externally-applied heat.
Excellent work Jeff! In your next video, can you keep the text cards on screen longer? Some of the more text rich slides were very difficult to read when they were on screen for only 1-2s.
Sure. Thanks very much for the feedback. It is hard to know how to strike a balance at time. I currently have them set to 2s but can up that to 4s and see how that works out.
As a teacher, I gotta say I love this video! Great job on this one!
Great video. Very informative.
Thanks. Great video, not just the usual rumour and conjecture.
Thanks!
One word regarding the content of this video, "Exceptional".
I use sunbright on all plastics, usually it works but not as well as the peroxide method. A faint yellow taint is still present on most of my projects, but no chemicals has been used , so it is a big plus environment wise.
This is a really important piece of work. Thank you.
I'm glad it was helpful.